SOLARlIDiE. 5 



eroiis volutions, internal face smooth, with a spirally twisted 

 median projection. 



Subfamily E UOMPUA L INA^J. 



Shell depressed, planorbiform ; whorls rounded, in contact 

 except in Eccyliomphalus, in which tliey are widely dissolute ; 

 spire flattened or involute. 



(Solariinas.) 

 Genus SOLARIUM, Lamarck, 1799. 



Shell depressed conic, angular at the periphery; aperture 

 subquadrangular, lip simple ; umbilicus with crenulated margins, 

 spiral, wide and perspective. 



Animal with large foot, notched in front, and having a very 

 pronounced marginal fold ; head large, furnished with two 

 tentacles which are short, thick, cylindrical and folded, with the 

 suture below; e3'es on swellings near the outer bases of the 

 tentacles; gill-cavity divided by a longitudinal fold. (Phi, 

 figs. 1, 2). 



Architectonica (Bolt. 1T98), Gray, is a synon3'm. 



Inhabits warm seas, world-wide. Fossil, more numerous. 

 Eocene. 



Subgenus Solarium, Lamarck (restricted). 



Surface of the shell strongly and closely sculptured longi- 

 tudinally, spirally sulcate and ribbed. Operculum corneous, 

 paucispiral, with the nucleus subexcentric. 



Solariorbis, Conrad, is a synonym. 



Subgenus Philippia, Gra^-, 1840. 



Shell without longitudinal sculpture, spiral sculpture nearly 

 obsolete. Operculum flattened ; whorls numerous, with the 

 nucleus subcentral, internal face bearing a subspiral calcareous 

 process. (PI. 1, fig. 9). 



Diaculus, Deshaj^es, 1863, is a synonym. 



Genus PLATYSCHISMA, M'Coy, 1844. 



Shell depressed, trochiform ; whorls somewhat rounded, 

 ornamented with small transverse striae; spire short; whorls 



