NOTICES TO CORRESPONDENTS.

E. H.-Your article is in type, and will appear in due

course.

B. BELFIELD.-Your specimen of female fern (Athyrium filix-fœmina) is very remarkable. It answers to the description of the var. trifidum, in Newman's "History of British Ferns," better than to any other, and we have no doubt this is the variety the specimen belongs to.

J. AITKIN. The white crust which you described as so abundant on the bark of beech-trees, and of which a speci. men was forwarded, is not of vegetable origin, and therefore not a fungus or lichen. It is of animal origin, formed of a species of Cynips, like the "apple-blight." At one time it was considered to be a fungus, and was then named Psilonia nivea.

R. STANDEN.-Your drawing is that of the Great Saw-fly (Uroceras gigas).

MRS. W.-You had better consult a practical nurseryman about the roots of your cherry-trees. His experience will at once lead him to say what you had best do to arrest the attacks of the insects and fungi.

C. L.-Read the paper on "The Formation of Chlorophyll," in the November number of 8.-G., for information as to whether sunlight affects a fire. You will there find experiments related which prove that it does.

R. W.-Genuine thanks for your hints as to the matter on our last page.

T. L.-Your specimen is evidently a stunted form of Delesseria alata.-W. H. G.

J. V. Your specimen of Bryopsis plumosa, with a so-called green parasitic growth attached, was forwarded to one of our best algologists for identification. He writes, "It looks like half a dozen different things, but it is so muddled together and so interwoven that I hardly know what to say of it. I have given what time I had to spare to it, and believe it to be some abnormal or undeveloped filaments of Bryopsis plumosa. I do not think it is a parasite."

J. P. GREELY.-The specimen inclosed was one of the wire-worms, the larva of a beetle. It is difficult to prescribe a remedy for its attacks. Perhaps some of our readers can, and will reply.

J. B. DAVIES.-Your fronds are undoubtedly those of Lastrea cristata, var. uliginosa, now very scarce. Pray, preserve the habitat.

H. G.-They are caused by an insect, a species of Cynips, and are known as "Oak-spangles' and "Buttons." See "Half-Hours in the Green Lanes." (London: Hardwicke). E. W.-The fern is Asplenium lanceolatum; the lichen a Cetraria.

W. E. SHARP.-Your eggs never reached us. Perhaps they were disposed of in the transit, unless well packed.

J. WILSON. The parasites on the badger were Trichodectes crassus, Denny's "Monograph," plate 17, fig. 3. It is distinguished by the notch on the top of its head.-I. O. W.

J. P. B.-We are sorry that your notice reached us too late for insertion in the December No. of Gossip.

J. M.-We shall be happy to get your Mosses named for you if you will forward them (properly packed) to our office. H. W. I.-Fungus on Pellia from Brazil is Uredo Marchantic-I think it is undescribed.-M. C. C.

J. H. S. J. (Lewes).-The fungus on leaves of Smyrnium olusatrum is Trichobasis petroselini.

EXCHANGES.

Clausilia Rolphii, C. laminata, and Helix Cartusiana, for Clausilia biplicata, Clausilia rugosa, var, dubia, Helix revelata, Helix lamellata, Limnæa glutinosa, and L. involuta.- Address, J. Fitz Gerald, 10, West-terrace, Folkestone.

PUPA of H. Pisi, for other common pupæ or ova.-J. Pickles, 12, 13, Warehouse-hill, Leeds.

FIFTY Australian Sea-weeds, named and mounted, for East or West Indian, North or South American Seaweeds, mounted or unmounted.-Address to be obtained from Mr. Hardwicke, 192, Piccadilly.

THE First Vol of "Grevillea," unbound, for Land or Freshwater Shells.-T. Hagger, Repton, Burton-on-Trent.

LEPIDOPTERA aud Pupa of P. Bucephala, and H. Pisi, in exchange for other Pupa or Birds' Eggs; many common species of each repuired.-Thos. H. Hedworth, Dunston, Gateshead.

BRITISH Land and Fresh-water Shells for American Land and Fresh water Shells.-David Whitehead, 70, Phoebe-street, Regent-road, Salford, Manchester.

POLARISCOPE Scales of Sea Buckthorn (S.-G., p. 278) and Vegetable Ivory, for other mounted objects.-Send list to C. C. Underwood, 25, Gloucester-place, Portman-square, London. I HAVE the following Duplicates:-Blysmus compressus ; Campanula patula; Cuscuta europæa; Epipactis grandiflora; Geranium phæum; Monotropa hypopitys; Neottia nidus-avis; Ophrys apifera; Orchis ustulata, O. elatifolia, O. pyramidalis; Orobanche minor; Polygonatum multiflorum; Thesium linophyllum. Desiderata-other plants.-E. A. Hall, Whatton Manor, Nottingham.

I have an Album (Oppen's) containing 702 stamps, also Lichen Hypnoides. Anything useful taken in exchange.Mr. W. Thomas, Ray Lodge, Lingfield, E. Grinstead.

3a, 16, 31, 46, 68, 122, 259, 286, 977, 1325, 1338, &c., Lon⚫ Cat., offered for 3b. 4 vars., 11 vars., 22, 24, 33, 36, 45, 47, 2286, 2356, 237, 238, 2406, 242, 243, &c.-John E. Robson, Sea View, Hartlepool.

LEPIDOPTERA and specimens of H. virgata, H. caperata, var. ornata, H. hispida, H. arbustorum, H. rotundata, &c., for other Shells and British Birds' Eggs.-W. K. Mann, 17, Wellington-terrace, Clifton, Bristol.

CAN any one oblige with living Plants, or Seeds, of Eleagnus, Deutzia, or Hippophæ rhamnoides (Sea Buckthorn)? Say what exchange.-J. G. R. Powell, Braw-hill House, Leek, Staff.

WANTED, well-mounted slide of Triceratium; will give a well-mounted slide in exchange.-F. M. Swallow, Blackrod, near Chorley, Lanc.

SECTION of Cuttle-bone, ground-plan (opaque), and of Charob-seed (polar), for other good objects.-Send list to R. H. Philip, 23, Prospect-street, Hull.

SECTION of Leg of Camel in exchange for other Microscopic objects.-J. M. Hoare, The Hill, Hampstead.

FOSSIL Diatoms from Isle of Mors, Jutland, in exchange for other good slides or Barbadoes polycistina, unmounted.Apply to F. Lazenby, Sarum-villas, Basingstoke.

BRITISH Lepidoptera and Coleoptera, Foreign and British Shells and Limaces offered for Foreign Shells, or British Land, Fluviatile, and Marine.-M. M., Post Office, Faversham, Kent.

"THE MICROSCOPE," by Jabez Hogg (fifth edition), and a good Writing Diamond, for well-mounted Microscopic Objects.-A. C. Rogers, Red Lodge, Bassett, Southampton. WELL-MOUNTED Microscopic Slides of Marine Algæ, 40 varieties, also some small Star-fish, unmounted, for good Slides.-R. T. Smith, 25, St. Alban's-street, Weymouth.

GooD specimens of Helix arbustorum, H. ericetorum, Clausilia laminata, C. rugosa, Planorbis vortex, Pupa secale, P. umbilicata, and Cyclostoma elegans for other Shells.-R. Taylor, 6 Everleigh-street, Tollington-park, N.

COLLECTION of 50 Species (160 specimens) of British Birds' Eggs arranged in trays, in box, for Microscopic material or Works on the subject.-R. Taylor, 6, Everleigh-street, Tollington-park, N.

COMMUNICATIONS RECEIVED UP TO THE 12TH ULT. FROMW. K. B.-F. K.-K. H.-A. C.-C. G. B.-E. R.-J. R. 8. C. -J.J. R. B.-G. G.-G. W. V. S.-W. H. B.-E. E.-T. W. W. -J.S.H.-J. A.-S. S.-E. G.-G. R.-H. B.-T. B. K.-J. H. -T. H. H.-J. P. B.-W. W. S.-E. M. M.-J. G.-H. G.W. S.-D. W.-S. T. P.-C. C. U.-J. W.-E. W.-C. E. F. G. -T. O. W.-R. S.-A. H. 8. T.-Dr. T. O. W.-C. W. L.-W. T.-H. T. M.-M. W. T.-H. A. M.-J. G. R. P.-J. H. M. -A. A.-H. W.-J. L. H.-A. C. L.-M. A. L.-R. W.-R. T. -A. S.-W. D. E.-C. E. B.-C. P. G.-W. H. W.-R. A. P. -J. O. H.-J. T.-R. T. S.-F. A. A.-W. C.-R. H. P.E. A. H.-A. S.-W. S. P.-F. M. S.-E. B. F.-F. B.-J. C. -H. E. W.-J. P.-C. J. W. R.-J. M. H.-W. K. M.-J. E. R. -G. B, C.-J. E.-F. L.-R. M. B.

N the year 1827 C. A. Agardh discovered several new diatoms, which he described in the Regensburg Botanical Journal, and men

tions for the first time the genera Micromega, Licmophora, and Homœocladia. The same algologist wrote more particularly of this family. in four theses, which appeared with the title "Conspectus Criticus Diatomacearum;" in the first and second he described a great number of forms, partly already known and partly new, under the genera Cymbella, Schizonema, Micromega,' Berkeleya (this genus was constituted by Greville in 1827), Homœocladia, Gloeodictyon, Hydrurus, and Gloenema. In the third part (1831) he gave the genera Gomphonema, Styllaria (=Podosphenia, Ehr.), Meridian, Licmophora, and Frustulia; in the last part (1832) Isthmia, Odontella, Desmidium, Achnanthes, Striatella, Fragilaria, Grammonema (belonging to the Desmidiea), and Melosira. (Kützing was wrong in referring Grammonema to Desmidies. This form is probably an imperfectly siliceous Fragilaria, and it is, moreover, a marine species.-F.K.) In the whole the author describes about 116 species of Diatomaceæ. Greville had already described (1827), in the "Scottish Cryptogamia Flora," vol. v., the genera Exilaria, Monema, and Berkeleya.

In 1828 Turpin founded the genus Surirella, and Gray, in 1830, the genus Biddulphia, from Conferva Biddulphiana and C. obliquata of the Eng. Bot. No. 110.

Thus, till the year 1832, stood the systematic labours on these microscopic organisms, most of the writers mentioned considering them partly as animals (the moving forms) and partly as plants (the fixed forms). Agardh, Lyngbye, and Leiblein advocated decidedly their vegetable nature; but, beside Schrank, there was none who decidedly advocated their animal character; of their life-history nothing was known beyond the thorough communications of Nitzsch, and the more superficial observations of Gaillon, that might have brought the question as to their nature nearer solution.

In the same year (1832) appeared the second Contributions to the Knowledge of the Minutest Organisms," by C. G. Ehrenberg. In this the Diatomacea were considered as decided animal forms, and were included with the infusoria under the family of "staff animals" (Stäbthierchen, including ¡Desmidiea); in the class of "stomach animals." (Magenthiere). But, at that time, stomachs were as little recognized by the author as mouth, entrails, or rectum; but a bivalve shell and a changeable foot (veränderliche Sohle) (like the Gasteropods) and said to stretch out the longitudinal cleft of both valves, was mentioned. Another communication from the same author followed in 1834, in which were described sixteen newly observed forms. The descriptions communicated in these observations are of the greatest importance, and are given with a care hitherto unknown in this field. The author had this advantage over his predecessors, that in his investigations he could make use of the best microscopes. (The best microscopes of this period probably did not equal in performance such as may now be obtained for four or five pounds. In 1834 Messrs. Goring and Pritchard published the "Micrographia," in which is a dialogue between Tobias Oldbuck, Esq., naturalist, and Mr. William Putty, optician, on the comparative merits of the old-fashioned simple microscope and the

C

newly-invented engiscope (or aplanatic microscope), the performance of metal reflectors (amician reflecting engiscope), and achromatic objectives are also discussed.-F. K.)

Within Navicula Amphisbæna he considered the coloured substance as an ovary, and took the lighter cysts appearing therein as polygastric stomach-sacs.

In the year 1838 appeared the great work by Ehrenberg "Die Infusionsthierchen als vollkommene Organismen," in which he still adhered to the animal nature of the Diatomaceæ, and fancied he saw openings or mouths, stomach-cells, sexual organs, and foot-like projections. The filamentous forms he compared to Polypi stems.

Since the first attempts to bring the Diatoms into several genera, the outward form of the shellcovered body, the manner in which the single individuals are united, and the presence or absence of stipes whereby they are attached, have been principally taken as the foundation of classifications since Ehrenberg introduced also the presence or absence of shell-openings for the distinction of genera; but the main groups were arranged according to the presence or absence of stipes, a mistake which caused the author to mention Lyngbye's Diatoma arcuatum not only as two different species, but also under two different genera, viz. as Tessella catena," and Striatella arcuata. His 154 species, contained in the work already mentioned, are mostly accompanied with very carefully drawn figures. In 1839 he published, in the Proceedings

to Europe in the transportation of lumber (Pflanzentransport), so that he obtained a view of the forms from forty-four different localities in America, from the Falkland Islands to Kotzebue Sound.

In the same year in which Ehrenberg's great work on the Infusoriæ appeared, A. de Brebisson had diligently studied the Algae of his neighbourhood (Falaise), the results of which he published in his "Considérations sur les Diatomées," in which he introduces the genera Cymbophora and Epithemia.

About this time Greville (in Hooker's "British Flora") and Harvey (in the "Manual of British Alga") became co-workers among the Diatomaceæ. The latest discoveries appeared to have been quite unknown to them; at least, they have no influence on their labours.

Ralfs has furnished the most recent work on British Diatoms in a single monograph, which is printed and accompanied with figures in the twelfth vol. of "Annals and Magazine of Natural History." Ralfs excels his predecessors in the correctness of his descriptions; but his figures are mostly crude (with the exception of those of Amphitetras, Biddulphia, and Isthmia).

CHAPTERS ON CUTTLES.

No. 3.

By W. H. BOOTH.

F. K.

of the European, Libyan, and Arabic Chalk Rocks, and the Chalk-marl from Microscopic Organisms." In this communication he described the new genera Coscinodiscus and Dictyocha. [The latter genus is now removed from the Diatomacea, with which it has no affinity.-F. K.] In 1840 Ehrenberg discovered that many of the fossil forms were still living in sea-water (also published in the Proceedings of the Berlin Academy). He also published the new genera Amphitetras, Ceratoneis, Grammatophora, Lithodesmium, Podosira, Triceratium, Tripodiscus, and Zygoceros. In the same year a further communication contained a description of about 100 new species; and the genera Amphipentas, Campylodiscus, Discoplea, and Himantidium. He also published, in 1840, his work on the extent and influence of microscopic life in North and South America. Professor Bailey had already, in 1838, given the outlines of American Bacillariæ in Silliman's "Journal of Science and Art," and had also especially reported on the fossil forms of North America.

Ehrenberg received abundant material from North America, and at the same time he received contributions from South America through his brother, Carl Ehrenberg. He also obtained earth from various parts of the Continent, which was brought

tion B, the Spirulide. The little Spirula, or Ram's-horn, is a shell familiar to most of us, though we may not be acquainted with the anima. that formed it. Many of these shells are brought by the Gulf Stream and strewed along the coast of

was generally supposed that it was an exterior shell very much like that of the Nautilus in its function. Such, however, was found not to be the case, for a living specimen was lately procured by Mr. Percy Earl on the coast of New Zealand, which proved that in this cuttle the shell is contained within the mantle, and is in no part external. There are three different species of Spirula, differing from each other but slightly: they are all divided into separate chambers connected by a siphuncle.

Fig. 21. Ceratites nodosus, from the Muschel-Kalk limestone, showing lobed chambers.

We now come to the second order of cuttles, the Tetrabranchiata, or "four-gilled." The animals of this order are all protected by an external shell, they progress in exactly the same manner as other cuttles; but their arms, which are very numerous, are not furnished with suckers. Three families only, the Nautilide, Orthoceratida, and Ammonitida, are contained within this order, many hundred dif

Fig. 22. Clymenia, from Devonian limestone, showing zig. zagged chambers.

ferent species of shells belonging to these three families are known, but of these three only are recent, all the rest being fossils. We are all well acquainted with the shell of the Pearly Nautilus (Nautilus pompilius), which will serve as a type for its family. The shell of a Nautilus, when cut into

two halves, appears to be divided into a number of cells (septa), which are connected by a small tube, the siphuncle. All the four-gilled cuttles have shells similarly partitioned off, although in some the shell is straight, in others only slightly spiral, and others often coiled. The Nautilus is furnished with a number of tentacles, which are of two kinds, those about the mouth being of a different description to those which serve as arms. It occupies the front cavity of the shell, and can shut itself in by means of two arms, to which is attached a leathery sort of hood corresponding to the operculum of some univalves. The other chambers which do not contain the body of the animal, but are connected with the heart by the siphuncle, which contains a membranous tube exactly fitting all the cavities, are used to float the animal. Although water could not gain access to the cavities, because the entire circumference of the mantle in which the siphuncle originates is firmly attached to the shell by a horny girdle quite impenetrable to any fluid, yet it is supposed that the chambers can be filled with a liquid from the pericardium, which compresses the air already contained in them, and so the centre of gravity is changed. By thus, so to speak, shifting its balance, the Nautilus rises to the surface or sinks down to the depths at will. Owing to the paucity of living specimens examined by scientific men, but little is positively known about the habits of the Nautilus. Mr. G. Bennet, I believe, was the first man of science who had the good fortune to obtain a living specimen. This gentleman was in Mare Kini Bay, near Erremanga, when a Nautilus was seen not very far from the ship, floating on the surface of the sea with the upper portion of the shell raised above water, and kept in a vertical position by means of the included air, and, in the words of the sailors, looking very much like a dead tortoiseshell cat in the water. On being captured the upper portion of the shell got broken by the boat-hook, as the animal was just sinking when caught. The shell is so well known that a description of it would be superfluous; but a few remarks on its ingenious structure, formed so as to resist the great pressure it would have to encounter when at the bottom of the ocean, may be of some interest. The shell is constructed in every way on the principle of the arch, so as to offer the greatest resistance to pressure, by making each part bear its share of the weight. In some fossil species the strength of the shell is greatly increased by its being formed into ribs, thus fortifying it in a man

Fig. 23. Ancient Belemnite,

(restored).

ner similar to that by which iron is strengthened by being corrugated. And, last of all, the divisions between the chambers serve as supports, acting as cross-beams, and enabling the shell to [resist all lateral and inward pressure. Probably more of the living animals have been lately observed, as they are by no means rare in the Indian seas, their favourite haunts being along the coral reefs. The Fiji Islanders are said to catch them by letting down large wicker baskets of the same construction as ordinary crab-pots, baited with crayfish, and loaded with stones to make them sink. After catching the Nautili they broil them, when they are reputed to be very good eating.

The good people of Whitby went farther than this, for they made plaster heads of snakes and fixed them on to the Ammonites; alleging that they were found in that condition. Ammonites are occasionally found of a great size, almost as large as a cartwheel, and in some parts are so plentiful as to be used for mending the roads. They are very generally distributed, most numerous in portions of the Oolitic system; two species found in England, at Whitby, have also been discovered at an elevation of sixteen thousand feet on the Himalayas.

Fig. 24. Goniatites sphæricus, from Carboniferous formation, showing angulated chambers.

Of the second family, the Orthoceratida, we have no examples, save in the fossil state. In the typical genus, Orthoceras (opeos, orthos, straight, and répas, keras, a horn), the shells are straight, and, as their name implies, very like a straight horn. Like the Nautilus, these shells are multilocular, and have their chambers separated by transverse plates, concave externally, convex internally, and connected by a siphuncle. Some species of this genus attain to a length of nearly six feet; their shells are found in great numbers in blocks of marble of a dark-red colour, from the limestone of Oeland. Of this marble many pavements of our public buildings have been constructed; amongst them part of that in Hampton Court Palace, and that in the Hall of University College, Oxford. Several other genera belonging to this family possess shells of very pretty and varied forms; of these, the genera Cyrtoceras and Gyroceras, are good examples. We now reach the last family, the Ammonitida, containing the well-known Ammonites and other kindred forms, which must have existed in great numbers during the Secondary epoch, as testified by the number of their shells which have been found. They are very similar to the Nautilus in most respects, and are far too well known to require description. The name of Ammonite is said to be derived from the Romans, who called it the " cornu Ammonis," or Ammon's horn. Another name is that of St. Hilda's beads, so called from a supposition that they were snakes turned into stone at that saint's prayer.

It now only remains for me to notice a class of shells which, from their structure, might be supposed to be closely connected with the Ammonites and other chambered shells; I allude to the Foraminifera, and more especially the Nummulites. These beautifully sculptured little shells, existing as they do in countless myriads on our coasts, the delight and great pleasure of the microscopist, are of much lowlier rank. They appear to be more closely allied to the Amabæ, animals (very nearly vegetables), nothing more than a piece of mucus, colourless, plastic, and just retaining voluntary motion. When one of these creatures approaches any minute plant or animal that cannot get out of its way, it so contorts itself as to send out branches or arms of its body, which clasp the prey all round, and make it embedded in the living mucus until quite absorbed. Thus, of very much lower organization than the Cuttles are the Foraminifera.