184 MR, J. G. GOODCHILD ON THK [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. Snc, 

 all the specimens of Atrelia to microscopic examination. Under a 

 ten-inch power the beak-area deltidial plates present some imma- 

 ture 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. We observed 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 sac- 

 like 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 hope further to investigate the matter. 



3. Observations on the Disposition of the Cubital Coverts in 

 Birds. By J. G. Goodchild, F.Z.S., F.G.S., H.M. 

 Geological Survey. 



[Eeceived Marcli ]6, 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 itvi 

 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 repre- 

 senting 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 



' Note. — More prolonged examination by daylight with different powers 

 showed these appearances to result from the partial overlapping of the cycloidal 

 scales of the shell-structure. Tlie presence of parallel rows of spicular pro- 

 jections was clearly revealed in the interior of the valves ; these occur at 

 i-egular distances from each other, running from the beak towards the margins 

 of the valves. — Aones Crane, April 26th. 



