504 CYMBULUDiE. 



Diacria trispinosa. 



Shell long, straight, anteriorly dilated, compressed on both sides, terminating 

 posteriorly in a very long spine, and armed with a short spine on each side. 



Hyalea trispinosa, Lesueur, in Blainville, Diet. xxii. 82. — Forbes and Hanley, 

 Brit. Moll. ii. 380, pi. 5, fig. 3. — Stimi'SOn, Shells of New England, 27, no descr. 

 (1851) ; Check Lists, 4 (1860). 



Diacria trispinosa. Gray, Brit. Mus. Pteropods. 



This species is admitted on the authority of Dr. Stimpson, who 

 says specimens are occasionally cast ashore at Nantucket. 



Family CYMBULIID^. 



Animal globular or ovate. Pins two, horizontal, opposite on each 

 side of the mouth, with a small intermediate lobe. 



Shell cartilaginous, slipper-shaped, rarely wanting. 



This family comprises four singular jiclagic genera with mem- 

 branous or cartilaginous shells, excepting Tiedemannia, which does 

 not appear to possess any membranous envelope. 



Ocmis PSYCHE, Rang. 1826. 



Body free, membranous, without any distinct head ; tentacles 

 none ; wings two, lateral, elongate, without any intermediate lobe. 

 Shell very thin and membranaceous. 



Psyche globulosa. 



Psyche globulosa, Rang, Ann. So. Nat. 1st ser. v. 283 (1825). — Rang and Souleyet, 



Hist. Nat. des Pterop. 72, pi. 7, fig. .5 ( 1852). — Gray, Br. Mus. Pter. 28 (1850). 

 Euribia globulosa, Gray, Brit. Mus. Moll. coll. P^ydoux and Souleyet, 11 (1855). 



Body round, diaphanous, mouth slightly arched, fins long, rounded 

 at their extremity, narrowed at their base, with a light shell-case 

 above. Viscera of a handsome purple, forming an ovoid mass, 

 suspended in the middle of the body. (Rang-.^ St. Pierre and 

 Miquelon. 



Family LIMACINID^E. 



Animal elongate, spiral ; the head indistinct ; mouth at the union 

 of the two fins and intermediate lobe, with two small labial swell- 



