180 Proceedings of the Mad. Lit. Society [xo. 1, 
by these curions little animals. The second species of which a 
single indiTidual only was obtained has the shell corered by a strong 
epidermis the lower edge of which is prolonged into a broad keel 
serving to sustain the shell in an erect position during the process 
of Bwimming. This species is probably new to Science. 
Several specimens of a species oi Glaucus, an aberrant gronp 
intermediate between Gastsopods and Ptkropods (although gene- 
rally included among the former^, were taken iu Lat 34 S. These 
are without shells but are furnished with lateral symmetrical append- 
ages which are supposed to be bronchiae and also serve for par- 
poses of locomotion. 
Dr. Traill's specimen differs from the c:r.:Tn:!i kind ani appears 
to have been considerably mutilated. It uiiv prove to be ne— . 
But the richest harvest was obtained in the class cf Piercpods. 
Of the 8 or 9 genera constituting the family of HyaJeida in this 
group, numerous specimens were obtained belonging to HyaUa^ 
Cleodora, Cutiera and Creseu or Theea and one species of Limacina. 
The genus Hyalea was particularly prolific of species. Some it is 
probable have now been met with for the first time. Their speci- 
fic characters are carefully pointed ont and all are faithfully repre- 
sented in the drawings. 
Mr. Traill has some excellent remarks on the analogy between the 
organization of the young of some kinds of Gastropod Moulttscs 
and that of the adult Ptebofod, and has observed that the young 
of the Cyprcta or Cowry shell when first released from the egg or 
c^^ksule and before they are able to crawl, exhibit a mode of pro- 
gression very similar to that of the Pxesopods. 
The greater part of the specimens described were captured in 
the night, the habits of most of the genera being more or less cre- 
puscular or nocturnal, except the genus Creseis which was often 
met with during the day. 
Dr. Traill's memoir was referred to the Committee of Papers, 
and wUl appear in the JoumaL 
