202 



Dr. J. G. Cooper read the following paper on some new genera 

 and species of California Mollusca collected by liim. 



The collection of the Geological Survey, made during the years 

 1861-62, contains many species of mollusca and shells, of which no 

 descriptions are to be found, and which we may therefore believe 

 to be new. But as they may have been collected either by the 

 Northwest Boundary Survey north of us, or by Mr. J. Xantus, at 

 Cape St. Lucas, it has been considered safest, in order to avoid 

 confusion, to send specimens or drawings of them to ]Mr. P. P. 

 Carpenter of England, ayIio has the above collections in his hands, 

 in order that he may compare our species with them and decide 

 whether they are really new. Meanwhile there are several species 

 of soft mollusca (without shells) which are so difficult to preserve 

 m a condition fit for description, that it may be presumed that they 

 are still undcscribed, and will not be described if in the collections 

 mentioned. Having made careful colored drawings of them wliilc 

 alive, the writer is enabled, with the assistance of the specimens in 

 alcohol, to prepare the following descriittions. Careful comparison 

 with the figures and descriptions of the nearest aUied forms, de- 

 scribed in the late works of H. & A. Adams, Cheuu, Gould and others, 

 make it probable that the determinations here made are correct : 



Strategus, nov. gen. 



From the Greek word for a general, m allusion to its l)rilhant 

 colors, resemblmg a mihtary uniform edged with blue and gold, and 

 hberally spotted with gilt buttons. It seems also to hold the high- 

 est rank in its order. 



Strategus inennis, n. sp. is the only species yet known. 



Ge7i. Char. — Form elongated cylmdrical, the body included in 

 the Avide reflexed borders of the foot, which nearly meet in the 

 median line above. Head and tail uncovered, each forming about 

 one-third the length of the animal. Foot extending forward as far 

 as the mouth, and backward nearly to the end of the tail. When 

 disturbed, the animal rolls over on its back and the foot envelopes 

 its whole body hke a cloak. The foot has no adhesive power, 

 motion being effected by gliding and twisting much as with ser- 

 pents — assisted by the support of the grass among which it hves. 



Head obtuse with an ear-hke fold of the skm at each corner, 

 resembhng a cat's head seen from above. Eyes moderate, placed 

 on the top of the head at the base of these folds. Tentacles two, 

 short, m front of the head on a hne with the eyes. Mantle little 

 developed, extending from the ear-like folds back to the posterior 

 thii'd of the body, and ending abruptly by a transverse fold. 



