110 GADINIID^. 



land, Pacific, Galapagos, Peru, Cape Horn, West Indies, W. 

 Coast of ]Sr, America. Fossil, 3 sp. Miocene — ; France. Type, 

 S. sipho, Sowerby (cii, 97 ). 



Shell somewhat like Patella ; apex subcentral, posterior ; mus- 

 cular impression horseshoe-shaped, divided on the right side by 

 a deep siphonal groove, which produces a slight projection on 

 the margin. 



Animal with a broad head, bilobed but not tentaculate ; eyes 

 sessile on prominent rounded lobes ; pulmonary chamber covered 

 by a lobe of the mantle ; the rudimentary branchiae form trian- 

 gular folds of the lining membrane of the mantle, connected by 

 a raphe. The Siphonarise are found between tide-marks, like 

 limpets. 



SIPHONARIA (restricted), Dall. Shell solid, porcellanous ; apex 

 central or subcentral ; provided with more or less elevated 

 radiating ribs or ridges, which by their projection render the 

 margin irregular. S. gigas, Sowb. 



LiRiOLA, i)all, 1870. Shell thin, horny; smooth, or furnished 

 with fine radiating lines, which do not interrupt the margin ; apex 

 marginal or submarginal, twisted to the left of the median line 

 in most of the species. S. thersites, Carp. 



ANISOMYON, Meek, 1860. (Allerya, Morch. Scutulum, Monts ) 

 Shell thin, fragile, with subcentral apex, spiral in young indi- 

 viduals, and obliterated siphonal fold. Jaw thin, flexible, 

 striated. S. patelliformiSj Meek and Hayden (cii, 95). The 

 type is a cretaceous fossil, but several recent shells also belong- 

 here. 



? HERCYNELLA, Kayser. Shell large, rounded in outline, unsym- 

 metrical, the summit drawn to one side ; surface finely radiately 

 or concentrically striated, with a strong fold proceeding from 

 the apex to the border, and a corresponding depression within 

 the shell. H. Beyrichi, Kayser. U. Silurian. 



Family GADINIID^. 



Characters those of the typical genus. 



Gadinia, Gra}^, 1824. 



Syn. — Mouretia, Sowb., 1834. Rowellia, Cooper, 1865. 



Distr. — 10 sp. Mediterranean, Red Sea, Africa, Peru, W. 

 Coast of N. Am. G. afra^ Gray (cii, 96). Fossil, 1 sp. Sicily, 



Shell obliquely conical ; muscular impression horseshoe- 

 shaped, the right side shortest, terminating at the siphonal 

 groove. 



Animal pulmoniferous, without gills ; rostrum bifid. 



