222 ERYCINIDiB. 



pallial line single and radiately grooved, anterior muscular scar 

 triangular, posterior oval. 



Galeomma, Turton 



Etym.- — Galee, weasel ; omma^ eye. 



Syn. — Hiatella, Costa (not DaucL). Parthenopea, Scacchi (not 

 Fabr.\ 



Distr. — 14 sp. Britain, Mediterranean, Mauritius, Pacific. 

 Fossil, 1 sp. Pliocene — ; Sicily. G. Turtoni, Forbes and 

 Hanley (cxx, 1). 



Shell thin, oval, equilateral, gaping widely below; invested 

 with a thick, fibrous epidermis ; beaks minute ; ligament inter- 

 nal ; teeth 0-1. 



Animal with the mantle-lobes united behind and pierced with 

 one siphonal orifice, margins double, the inner with a row of 

 eye-like tubercles ; gills large, subequal, united behind ; palpi 

 lanceolate, plaited ; foot long, compressed, with a narrow flat 

 sole. 



The Galeomma spins a b^^^ssus, but breaks from its mooring 

 at will and creeps about like a snail, spreading ovit its valves 

 nearly flat. — Clarke. 



THYREOPSis, H. Ads., 1868. Shell resembling Galeomma, nearly 

 equilateral, subtriaugular, beaks slightly tumescent, and with 

 the whole of the ventral margins widel}^ gaping. G. coralliojjhaga, 

 H. Ad. (cxx, 2, 3). Mauritius. 



Scintilla, Desh. 



Distr. — 53 sp. Philippines, North Australia. Fossil; Eocene. 

 C. Philippinensis, Desh. (cxx, 4). 



Shell transversely oval, obtusely rounded at the sides, equi- 

 lateral, thin, shining, sometimes a little gaping ; ligament 

 internal, oblique ; two diverging cardinal teeth in the left valve, 

 one in the right valve ; lateral teeth posterior, one in the right, 

 two in the left valve ; pallial impression simple, 



Passya, Deshaj^es, 1852. 



Distr. — P. UugeniiyDesh. (cxx, 5). Eocene; Paris Basin. 



Shell regular, modioliform, triangular, depressed, greatly 

 gaping on both sides ; beaks anterior ; hinge short and narrow, 

 with a single tuberculiform tooth ; ligament internal ? mus- 

 cular impressions small, submarginal; pallial line simple. 



Libratula, Pease, 1865. 

 Distr. — L. plana, Pse. On coral. Pacific Isles. 

 Semilunar, much compressed (like a Placuna), slightly gaping 

 all round, cardinal margin erenulated, cartilage median, internal. 



