114 LIMACINID^. 



of arrangement for the MoUnsca 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 BlainviUe. 



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

 internal. 



Family I. LIMACI'NID^, Gray. 



Body small, spiral. 



Shell heHciform and sinistral : mouth oval, with an angu- 

 lated base: operculum soHd, 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. 



