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Show 184 MR. J. G. GOODCHILD ON THE [Apr. 6, lat., in the Arctic Ocean to the Canaries in the South Atlantic, and as far as lat. 32° south of the Equator in the Southern Pacific Ocean. The specimens will eventually be placed in the Davidson Collection in the British Museum. P.S.-Since my paper on Atretia brazieri was writtten, I have submitted with my friend Mr. J. E. Haselwood, F. R. Micr. Soc, all the specimens of Atretia to microscopic examination. Under a ten-inch power the beak-area deltidial plates present some immature features similar to those figured by Morse in his 'Embryology of Terebratulina.' The scaly structure of the shell is very apparent; there are no perforations. W e observe! two long slender narrow muscular scars, with a diamond-shaped central one in the interior of a ventral valve. The marginal borders of the largest specimen seemed raised or swollen. The most puzzling appearance occurs on some brown patches on the shell, consisting of circular and elongated saclike aggregations. If these bodies are a feature of the shell-structure, it seems strange they should be visible in portions of the surface only 1. I hope further to investigate the matter. 3. Observations on the Disposition of the Cubital Coverts in Birds. By J. G. G O O D C H I L D , F.Z.S., F.G.S., H.M. Geological Survey. [Received March 16, 1886.] The prominent position occupied by the cubital coverts in most living birds renders their correct delineation a point of so much importance in any figure intended for zoological purposes that it is perhaps hardly necessary to offer any apology for submitting a few observations upon that subject for the consideration of the Fellows of this Society. Both ornithologists and zoological artists have, of course, long been aware of the existence of considerable diversity both in the relative proportions and in the mode of arrangement of these feathers in various groups of birds ; but it seems never to have occurred to any one that these variations are of such a nature as to admit of their being reduced to any system of classification. This oversight may be due to the fact that the specimens made use of for scientific purposes have necessarily been either spirit-specimens or else skins flat or mounted. In the case of the skins especially, such specimens cannot, as a rule, be at all depended upon as representing the natural order of the feathers in a living state; and consequently ornithologists have been led to believe that the subject under notice was not worth any serious attention. But a careful 1 N O T E . - M o r e prolonged examination by daylight with different powers showed these appearances to result from the partial overlapping of the cycloidal scales of the shell-structure. The presence of parallel rows of spicular projections was clearly revealed in the interior of the valves ; these occur at regular distances from each other, running from the beak towards the margins of the valves.-AGNES O K A N E , April 26th. |
