1885.] General Characters of the Genus Cymbulia. 251 



II. " On the General Characters of the Genus Cymbulia." By 

 John D. Maodonald, M.D., F.R.S., Inspector-General R.N. 

 Received March 21, 1885. 



The purely pelagic habit of the interesting order of Pteropods 

 places them so far beyond the reach of zoologists in general, that the 

 opportunities of examining them in a living or recent state are few 

 and far between. I have myself been fortunate enough to obtain, 

 from time to time, nearly all the leading genera of the order in 

 question, but, singularly, have never fallen in with Cymbulia. 



Judging from the figures and descriptions of this genus given by 

 naturalists, it always appeared to me as if both animal and shell were 

 taken end for end so as to render all the descriptive relationships 

 ambiguous ; but it was only a short time ago that I was enabled to 

 investigate the point practically through the kindness of a naval 

 friend who brought me some specimens of Cymbulia Peroni from the 

 Indian Ocean. 



The result of examination proved the impression above expressed to 

 be a correct one, while other particulars of interest also revealed them- 

 selves. I found that the attachment of the animal to the shell was so 

 slight, and the visceral mass so short and rounded, that by incautious 

 handling the animal very readily came away, and here I believe is the 

 whole secret of the matter, for, on attempting to place it in situ again, 

 one would be very likely to turn it upside down, and the error would, 

 of course, be propagated in otherwise, possibly, excellent figures and 

 descriptions. It might be mentioned here that the great malacologist 

 De Blainville gave the generic name of Gastroplax to an Umbrella 

 which he found with the broad surface of the foot accidentally adherent 

 to the shell, so that we need not wonder at what anybody else might 

 do under similar circumstances. 



Mr. S. P. Woodward, in his Manual of Mollusca, thus characterises 

 Cymb ulia : — 



Shell cartilaginous, slipper-shaped, pointed in front, truncated 

 posteriorly, aperture elongated ventral. 



Animal with large rounded fins connected ventrally by an elon- 

 gated lobe; mouth furnished with minute tentacles, lingual teeth, 

 1,1,1 ; stomach muscular, armed with two sharp plates. 



In keeping with the above description, the figure given of Cymbulia 

 proboscidea (after Adams) shows the toe of the slipper in front like a 

 rostrum, probably suggesting the specific name proboscidea, for the 

 animal itself presents no appearance of a proboscis. In De Blainville's 

 figure, however, a protrusion from the generative orifice might be so 

 interpreted ; but unfortunately, though the shell is given in its 

 natural position, the animal is turned upside down. The eyes men- 



