GASTEROPODA. 145 



Type, D. laciuiata. PL X., fig. 13. (= T. delphinus, L.) 



Shell orbicular, depressed ; whirls few, angiilated, rugose, or spiny ; aper- 

 ture round, pearly ; peristome continuous ; umbilicus open ; operculiun liorny, 

 many-whirled. On reefs, at low-water. 



Animal without head-lobes ; sides lobed and cirrated. 



Dist7\, 20 sp. Red Sea, India, Philippines, China, Australia. 



Fossil, 30 sp. ? Trias ? — Miocene — . Europe, 



Suh-genera. Liotia, Gray. L. gervillii. PI. X., fig. 14. Apertm-e 

 pcarlj'', with a regular, expanded border. Opcrc. multi-spiral, calcarious. 

 Distr., 6 sp. Cape, India, Philippines, Australia. Fossil, Eocene — . Brit., 

 France. 



Collonia, Gray, 1850. C. marginata. PI. X., fig. 16. Peristome sim- 

 ple. Operc. calcarious, with a spii-al rib on the outer side. Distr., Africa. 

 Fossil, Eocene — . Paris. 



Cyclostrema, Marryat. C. canceUata, PL X., fig. 15. SheU nearly dis- 

 coidal, cancellated, not pearly ; aperture round, simple ; umbilicus wide. 

 Operc. spii-al, calcarious. Distr., 12 sp. Cape, India, Philippines, AustraKa, 

 Peru. In 5 — 17 fathoms. Serpularia, Roemer, has the whiiis smooth and 

 dis-united. Eocene, Paris. 



Adeokbis, Searlcs Wood. 



Type, A. sub-carinatus. PL X., fig. 17. 



Shell minute, not nacreous, depressed, few- whirled, deeply umbilicated ; 

 peristome entire, nearly continuous, sinuated in its inner side, and slightly so 

 externally. Operc. sheUy, multi-spiraL 



Distr., W. Indies — China. Low-water to 60 fathoms. 



Fossil, 5 sp. Mioceue — . Brit. 



EuoMPHALUS, Sowerby. 



Eti/m., eu, wide, and omphalos, umbilicus. 



Syn., schizostoma, Bronn. j\Iaciiu-ea, Leseuer. Ophileta, Vaniixem. 

 Platyschisma, INIcCoy. 



Type, E. pentagonalis. PL X., fig. 18. 



Shell depressed or discoidal ; whirls angular or coronated ; aperture poly- 

 gonal ; umbilicus very lai-ge. Operc. shelly, round, multi-spiral (Salter). 



Fossil, SO sp., L. sil. — Trias. N. America, Em-opc, Australia. 



Snb-gemi.s. Phanerotinns, J. Shy. 1840, E. cristatus, Phil. Carb. lime- 

 stone. Brit. SheU discoidal ; whirls separate ; outer margin sometimes 

 foliaceous. 



Stomatella, Lam. 



Etym., diminutive of stoma, the apertm-e. 



TT/pe, S. imbricata. PL X., fig. 19. 



Shell car-shaped, regular ; spire small ; aperture oblong, very large and 



H 



