gested by Huxley) of the worms and echinoderms, it was most important that Metznikoff's observations should be repeated, and if possible the genus of annelids, of which Tornaria was the young, accurately ascertained. The annelid raised by Metznikoff was most peculiar and, in absence of other evidence, he suggested the possibility of its being a young Balanoglossus. I have been able this summer to raise Tornaria and to obtain young annelids somewhat older than those observed by Metznikoff, tracing at the same time the development of the branchia as diverticula from the œsophagus, and also to find the young annelid of Tornaria a species of Balanoglossus (of which the adult is quite common at low water mark at Newport and at Beverly, Mass.), but slightly older than those raised directly from the Tornaria stage. The details of this interesting embryology will shortly be published. A. AGASSIZ. THE PECULIAR COLORATION OF FISHES, mentioned by your correspondent Richard Bliss, is, it appears to me, susceptible of easy explanation. The pigment-cells containing the brilliant crimson, adorning the skins of cyprinidæ and other fishes, are readily opened and closed under excitement and other influences. When brilliant Cyprinid are confined in aquaria they speedily lose their color by the closing of the cells, but it may be readily restored by scratching the surface with the point of an instrument, which reopens the cells. Even specimens freshly placed in weak alcohol may sometimes be made to display bright color by the same process. When the alcohol is strong, it may so contract the surrounding tissue as to expose the contents of the cells, as in the case observed by Mr. Bliss. -Edw. D. Cope. A NEW SPECIES OF PASSERCULUS FROM EASTERN MASSACHUSETTS. In December, 1868, I took a sparrow at Ipswich which was then supposed to be Centronyx Bairdii. In the autumn of 1870, I took two more of the same species, also at Ipswich; but upon visiting the Smithsonian Institution this spring and comparing these specimens with the original C. Bairdii, I have come to the conclusion that they are specifically distinct. They are closely allied to the savanna sparrow and evidently belong to the same genus; I therefore propose to name the Massachusetts bird Passerculus princeps, the large barren ground sparrow. The Centronyx Bairdii should also, I think, be referred to the genus Passerculus, for I can see no good generic character by which it can be separated. A description and figure of this new Passerculus, will be found in the "Naturalists' Guide" (page 112) under the name of Centronyx Bairdii, with a history of the capture of the first specimen and also an account of how this name came to be applied to it. It will likewise be understood that the name of Centronyx Bairdii, given in a notice in the May number of the NATURALIST (page 307) by Mr. Brewster, should read Passerculus princeps. The Thalasseus Havelii, mentioned by Mr. Brewster in the same article, should also read Sterna Forsterii, for I have become convinced by carefully studying a large number of specimens that the Thalasseus Havelii Sterna Havelii of authors, is the young of Sterna Forsterii. — C. J. MAYNARD. GEOLOGY. OIL CREEK PETROLEUM KNOWN IN THE LAST CENTURY.-At a meeting of the California Academy of Sciences, July 15th, Mr. R. E. C. Stearns presented a communication, embodying the following extract from the Massachusetts Magazine published in the year 1789, Vol. i, p. 416, showing that the existence of petroleum in Pennsylvania was known at that period : "In the northern part of Pennsylvania, there is a creek called Oil Creek, which empties into the Alleghany river, It issues from a spring, on the top of which floats an oil similar to that called Barbadoes tar; and from which one man may gather several gallons in a day. The troops sent to guard the western posts, halted at this spring, collected some of the oil and bathed their joints with it. This gave them great relief for the rheumatism with which they were afflicted. The water of which the troops drank freely operated as a gentle purge." MICROSCOPY. SUCCESSIVE POLARIZATION OF LIGHT.-This curious scientific procedure has been accomplished in connection with the ordinary polarizing microscope, by Mr. J. W. Stephenson. In the selenite fitting of the polarizer, between the polarizing prism and the stage, he places, mounted so as to have a rotating movement of its own, a truncated glass prism having its broadest face silvered by the sugar of milk process, and its other faces so situated that light, polarized by passing through the Nicol's prism in a direction parallel to the silvered surface, is refracted on entering the prism, meets the silvered surface at an angle of 72° and is, after reflection, refracted on leaving the prism into a course parallel to that at which it entered. Some of the curious effects produced are mentioned in the Transactions of the Royal Microscopical Society. A DOUBLE ERECTING BINOCULAR. In the Report of the Croydon Microscopical Club, it is stated that at its last annual meeting there was exhibited an erecting binocular on Mr. Stephenson's plan, made double so that two persons could examine the object at the same time. J ANGULAR APERTURE OF THE EYE.-It having been carelessly assumed that in order to obtain a perfectly natural effect, the lenses of a photographic camera must be reduced to a linear aperture in., the average diameter of the pupil of the human eye, and that a large aperture gives objects differently from ordinary vision, Mr. G. S. Cundell observes, in the "Monthly Microscopical Journal," that the ocular focus is only about 8 in., and therefore only four times its linear aperture. A corresponding size of camera lens having 12 inch focus would be 3 inches, not inch. Such a lens, so far as aperture is concerned, would be as free from aberrations and distortion" as the human eye. For the sake of stereoscopic effect he would use a lens of 21 inches diameter, that corresponding with the average distance apart of the human eyes, and reproducing the object, a head for instance, as we see it in nature, without the hard, cutting lines of monocular vision, which all painters deprecate and avoid. NOTES. WE take pleasure in calling the attention of our readers to the publication, in another portion of this number, of the several memorials made to the Commissioners of the Central Park in New York, relative to Dr. Hawkins, and the restoration of his work so wantonly destroyed by order of Mr. Hilton, who, we understand, is no longer in charge of the works of art and nature which he evidently did not have the education fully to appreciate. As these memorials are the expression of the most cultivated and influential class of citizens of New York, and can but meet with a warm response throughout the country, we trust that the present Board of Commissioners will fully realize the importance of restoring Dr. Hawkins' work and of allowing him to extend the very instructive series which he had planned. Not only does it devolve on the Commissioners to render justice to Dr. Hawkins, but also, by the restoration of the work and the reinstatement of Dr. Hawkins, to remove a blot from the fair fame of American science. It seems as if the interference with the work of scientific men and their snubbing by the " Heads of Departments" had been epidemic of late, for not only have we to regret the treatment of Dr. Hawkins and Dr. Parry in this country, but also the equally outrageous treatment of Dr. Hooker by the Head Commissioner of the Kew Gardens in England, as lately made public in "Nature." Are we really going back to the early days of science, when a scientific man was looked upon as a subject for the mad house, or is it owing to the fact that "brains are scarce in high places?" We take this occasion to correct an impression which we find is held by some of our readers relative to the American Museum of Natural History, which is supposed by many persons not acquainted with the complex system of the Central Park, to be under the same government as that which Mr. Hilton represented, and that its officers were in a measure responsible for the outrage perpetrated. Such is not the case, and we should feel great regret if any remarks of ours had been construed to the disadvantage of that institution, which we believe to be doing good work and worthy of all assistance from scientists throughout the country. [Wishing to give the address by Prof. Gray in this number we have been obliged to postpone a large amount of Miscellaneous matter which was in type. - EDs.] ANSWERS TO CORRESPONDENTS. C. B. G., New York.-The spider is Epeira spinea of Hentz. BOOKS RECEIVED. Preliminary Description of new Tertiary Mammals. Part iii. By Prof. O. C. Marsh. Pub lished Aug. 13, 1872. (Received, Aug. 14, 1872.) 8vo. pp. 9. From the American Journal Sciences and Arts. Sept. 1872. Note on Tinoceras anceps. By O. C. Marsh. Published, August 24, 1872. (Received Aug. 26th,) From Amer. Jour. Sci. Arts, Oct. 1872. Proceedings Academy Natural Sciences, Philadelphia. 8vo. pp. 73-88. July 16, 1872. pp. 106120. (Received July 25th.) Transactions of the Imperial Botanic Garden of St. Petersburg. Vol. 1, No. 1. 8vo. Grevillea, a monthly Record of Cryptogamic Botany, August, Vol. i. No. 2. London. Edited by M. C. Cooke. 8vo. pp. 16. Notice of some New Tertiary and Post-Tertiary Birds. By Prof. O. C. Marsh. Published Aug. 30, 1872. (Received Aug. 31.) From the Amer. Jour. Sc. Arts. Oct. 1872. 8vo. pp. 8 Preliminary Description of New Tertiary Reptiles. By Prof. O. C. Marsh, Part 1. Published Sept. 6, 1872. (Received Sept. 9, 1872.) From Amer. Jour. Sci. Arts. Oct. 1872. 8vo. pp. 7. Preliminary Descriptions of New Tertiary Mammals. Part iv. Published August 17th, 1872. From the American Journal of Science. Sept. 1872, Die Grundlagen des Vogelschutz gesetzes. Von G. R. v. Frauenfeld. Wien. 1871. 8vo. pp. 12. Die Wirbelrauna Niederosterreichs. Von G. R. v. Frauenfeld. Wien, 1871, 8vo. pp. 16. Der Vogelschutz. Von G. R. v. Frauenfeld. Wien. 1871. 8vo. pp. 48. AMERICAN THE NATURALIST. Vol. VI. - NOVEMBER, 1872.-No. 11. NOTES ON ABORIGINAL RELICS KNOWN AS BY JOHN G. HENDERSON. Ar various points in the United States from the Atlantic Ocean to the Pacific, the curious aboriginal relics which form the subject of this paper have been found. In the absence of any other name for them they have been generally designated as "Plummets," a name suggested by their similarity to the implements of that name, used by civilized man, for the purpose of determining perpendicular and horizontal lines. They are made of copper, stone and iron ore, and are found both upon the surface of the ground and at various depths in the earth, sometimes as many as thirty feet below the surface. They have been found in the mounds of Ohio, at the foot of the "Bluffs" of the Mississippi in apparently undisturbed drift clay, and in the auriferous deposits of Table Mountain, California. A singular almond-shaped flint implement, found among the other relics of art of the mound builders, for a long time puzzled archæologists, but at length the problem was solved by finding a number of them in an Ohio mound, lying side by side, indicating that by having strips of wood securely fastened on each side, they had once formed part of a sword-like weapon, like what was found in the hands of the natives when Cortez landed in Mexico, and proved so effective, that a man could be cut in two with Entered according to the Act of Congress, in the year 1872, by the PEABODY ACADEMY OF SCIENCE, in the Office of the Librarian of Congress, at Washington. AMER. NATURALIST, VOL. VI. 41 (641) |