SOLARIID^E. 5 



erous volutions, internal face smooth, with a spirally twisted 

 median projection. 



SUBFAMILY EUOMPHALIN^. 



Shell depressed, planorbiform ; whorls rounded, in contact 

 except in Eccyliomphalus, in which the}' are widely dissolute ; 

 spire flattened or involute. 



(Solariinse.) 

 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; eyes on swellings near the outer bases of the 

 tentacles; gill-cavity divided by a longitudinal fold. (PI. 1, 

 figs. 1, 2). * 



Architectonica (Bolt. 1798), Gray, is a synoi^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, Gray, 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). 



Disculus, Deshayes, 1863, is a S3 r non}'m. 



Genus PLATYSCHISMA, M'Coy, 1844. 



Shell depressed, trochiform ; whorls somewhat rounded, 

 ornamented with small transverse striae ; spire short ; whorls 



