110 ‘GADINIIDA. 
land, Pacific, Galapagos, Peru, Cape Horn, West Indies, W. 
Coast of N. America. Fossil,3 sp. Miocene—; France. Type, 
S. stpho, 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 branchiz form trian- 
gular folds of the lining membrane of the mantle, connected by 
a raphe. The Siphonariz 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, Dall, 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. 8S. thersites, Carp. 
ANtIsoMYON, 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. patelliformis, 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. 
Famity GADINIID#. 
Characters those of the typical genus. 
GADINIA, Gray, 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. 
