242 ARCHITECTONICID.E. 



deeply umbilicated, umbilicus wide and spiral, with the 

 margin crenulated ; aperture nearly quadrangular, peri- 

 treme thin and simple. 



Sy)}. Solarium, Lam., not Spix. Physeter, Humph., 

 not Linn. 



Ex. A. perspectiva, Linnaeus, pi. 25, fig. 6. Oper- 

 culum, A. perspectiva, fig. 6, a, 6, h. Shell, A. per- 

 spectiva, fig. 6, c. 



The ovate, flat, subspiral operculum, and the angulated, 

 trochiform shell, distinguish this genus from Torinia. The 

 species are usually from tolerably deep water, and are not 

 littoral in their habits. 



Species of Architectonica. 



aspera, Hinds. laevigata, Lam. 



australis, Chem. maxima, Phil. 



cancellata, Krauss. modesta, Phil. 



discus, Phil. nobilis, Bolt. 



dorsuosa, Hinds. perdix. Hinds. 



formosa, Hinds. perspectiva, Linn. 



fragilis. Hinds. picta, Phil. 



fuliginosa. Hinds. purpurata, Hinds. 



granulata, Lmn. quadriceps, Hinds. 

 incisa, Phil. 



Genus TORINIA, Gray. 



Operculum circular, elevated, conical, of many whorls. 



Shell orbicular or elevated, last whorl rounded at the 

 periphery, deeply umbilicated, umbilicus moderate ; 

 aperture rhombic ; outer lip thin, simple. 



Si/fi. Heliacus, D'Orh. 



Eoc. T. infundibuliformis, Chemnitz, pi. 25, fig. 7. 



