114 LIMACINID.E. 



of arrangement for the Mollusca in an ascending series 

 will thus stand : Class 1. Brachiopoda. 2. Conchifera. 

 3. Solenoconchia. 4. Gasteropoda. 5. Pteropoda. 6. 

 Cephalopoda. 



Order I. THECOSO'MATA, De Blainville. 



BODY enclosed in a shell : head more or less indistinct : gills 

 internal. 



Family I. LIMACI'NID,E, Gray. 



BODY small, spiral. 



SHELL heliciform and sinistral : mouth oval, with an angu- 

 lated base: operculum solid, glassy, ear-shaped, and few- 

 whorled. 



Genus SPIRIA'LIS*, Eydoux and Souleyet. PI. IV. 



f. 4. 



So little is known of the genus Limacina (the only 

 other recorded member of the family as distinguished 

 from Spirialis), that I must refer to the general descrip- 

 tion for the characters of the present genus. Perhaps 

 Spirialis does not differ from Limacina, in which case 

 Limacina, being older, should be the generic name. S. 

 rostralis of Souleyet, which has a discoidal shell, with 

 a curved and prominent beak, may be the type of a new 

 genus, to be called Embolus. 



Gray, H. & A. Adams, and Morch have lately adopted 

 Heterofusus as the generic name, on Fleming's autho- 

 rity. But this name (which is prior to Spirialis, and 

 subsequent to Limacina) was unaccompanied by any 



* Having a spire : a barbarism. 



