« AnteriorContinuar »
there remains doubtless a rich harvest for future collectors. Then follow the list, which we must refer our readers to.
Is Bipah'um allied to the Leeches ?—Mr. H. N. Moseley, M.A., who has described the anatomy of this creature in the “Proceedings of the Royal Society ” [Feb. 20], states that in considering the general anatomy of Bipalium, it is impossible to help being struck by the many points of resemblance between this animal and a leech. Mr. Herbert Spencer has, in his “ Principles of Biology,” placed a gulf between Planarians and leeches, by denoting the former as secondary, the latter as tertiary aggregates, so called because consisting of a series of secondary aggregates formed one behind the other by a process of budding. It is obvious, however, that a single leech is directly comparable to a. single Bipalium. The successive pairs of testes, the position of the intromittent generative organs, the septa of the digestive tract, and most of all, the pair of posterior ceeca, are evidently homologous in the two animals. Further, were leeches really tertiary aggregates, the fact would surely come out in their development, or at least some indication of the mode of their genesis would survive in the development of some annelid. Such, however, is not the case. The young worm or leech is at first unsegmented, like a Planarian, and the traces of _ segmentation appear subsequently in it, just as do the protovertebrze in vertebrates, which Mr. Spencer calls secondary aggregates. If Mr. Spencer’s hypothesis was correct, we should expect to find at least some Annelid developing its segments in the egg as a series of buds. It is not, of course, here meant to be concluded that Annelids are not sometimes in a condition of tertiary aggregation, as Nais certainly is when in a budding condition, but that ordinarily they are secondary and not tertiary aggregates, and if so, then so also are Arthropoda.
A Medal to Mr. Carter.—A Royal Medal has been awarded to Mr. Henry John Carter, F .R.S., for his researches in Palaeontology and Zoology, on the Infusoria and Rhizopoda, and the root-cell of the Chara; but more particularly for his inquiries into the Natural History of the Spongiadae.
Zoological Society's Papers on Comparative Anatomy-Besides the many very valuable papers which have been published during the past quarter on purely zoological subjects, some admirable communications have been made on questions of Comparative Anatomy. Foremost among these was Mr. Kitchen Parker's (F.R.S.) able communication on the osteology of certain orders of birds, and also two papers by Mr. A. H. Gar-rod, the able anatomist of the Society. One of these (J an. 7th) was on a peculiarity in the termination of the anterior margin of the nasal bones of certain birds, according to which the Schizognathee of Prof. Huxley might be divided into two groups, to be called Schizorhinae and Holorhinae; and the other (Jan. 21st) was upon the visceral anatomy of the Sumatran Rhinoceros (Oeratorhz'nus Sumatrensis) based on aspecimen of this species lately living in the Society's Gardens.
~ THE tendency of words to degenerate in meaning has frequently been commented on by philologists, and to the more commonly known examples may be added the term ‘ parasite.’ Originally, in early Greek times, applied to the members of a college of priests (wapdrn'ror) it possessed simply its grammatical meaning of taking meals in common, but later it came to signify living at another’s expense, and was then applied to the contemptible toady and flatterer—one of the stock characters in Greek and Roman comedy—who would put up with any indignity from his patron for the sake of food and lodging. This character, which the social habits of classical times seem to have brought to great perfection, is by no means extinct in our days, though the objects sought by such voluntary degradation may be generally higher than mere creature enjoyments. The word is now however rather rarely applied to human beings, nor are we here concerned with such a use of it. In science also, the term parasite is given to beings which live upon others in the sense of getting from them their food, and is applied to animals which batten upon others, and to plants which are attached to, and live upon the juices, either of animals or of other vegetables. Such habits, inimical to other creatures, are possessed by a very large number of plants. Probably all the Fungi are parasites, and a good many attack the lower animals, among insects frequently causing their death; whilst even the body of man himself is the suitable soil for about a score of minute species. Of these lowly organised plants, it is not however intended to speak, and indeed their mode of parasitism is very difi'erent from that of the flowering plants which follow that mode of life. Among the Phanerogams, we find that there are only five or six natural orders all the members of which are parasitic; but there are isolated genera, or species scattered through about a. VOL. KIL—NO. XLVIII. Q
dozen other families. A list, which might probably be somewhat enlarged, is given below, upon which it may be remarked that Monocotyledons are few, and that none of the Dicotyledons are polypetalous (unless it be preferred to consider Balanopho
'raceoe, as belonging to that division)~—- '
What is called “ habit,” is a very fallacious guide to affinity, and has frequently proved so to even experienced systematists. It mainly results from modifications of the organs which for purposes of classification are of minor importance. Some of the parallelisms in outward appearance between plants with little real affinity have been noticed by A. W. Bennett, in an article in this Review for January 1872, and the matter is of that curious and suggestive character which leads to many speculations. The parasitic facies is a very marked one, and has naturally had an undue prominence assigned to it by some systematic botanists. Lindley and Endlicher, for example, created a class under the name of Rhizogens or Rhizantheae to include.the orders Rafiiesiacew, Cytinaceaz and Balanopho/racece, which was considered to be intermediate between thallogenous Cryptogams (like the Fungi) and Endogens. Though these eminent authors endeavbured to support their views by variousarguments drawn from supposed constant peculiarities of the embryo and the tissues, the group was no doubt founded chiefly on the habit of the plants composing it. This, however, results.