GLAUCOMYIDA, 183 
Liocyma, Dall, 1870. 
Distr.—2 sp. L. fluctuosa, Gould (exxiii, 87). 
Shell small, ovate, concentrically striated, compressed, nearly 
equivalve e and rather thin; there are in each valve thr ee cardinal 
teeth, the middle one cleft ; pallial sinus small. 
Baropa, Stoliczka, 1870. 
Distr.—B. fragilis, V’Orb. (exxi, 1-3). Cretaceous. 
Shell very much elongated. very inequilateral, with subparallel 
upper and lower margins laterally compressed, pallial sinus 
moderate, horizontal or nearly so, obtuse at the end ; hinge with 
three car dinal teeth in each valve, the posterior of w hich is very 
much elongated and sometimes ‘longitudinally furrowed; the 
two other teeth sometimes appear as one widely bifid tooth ; 
surface of valve smooth, only with concentrie¢ striw of growth. 
ICANOTIA, Stoliczka, 1869. Form similar to the last, inner 
edge of the shell anteriorly somewhat thickened, surface covered 
with radiating striz and ribs, strongest on the posterior upper 
slope. Psammobia impar, Zittel. 
Famity GLAUCOMYID2. 
Shell transverse, with a greenish epidermis. Siphons very 
long,compressed, nirited nearly to the extremity, which is fringed ;_ 
foot large, lineuiform, compressed, subcarinated. 
Guaucomya (Bronn), Gray. 
Etym.—Glaucos, sea-green ; mya, mussel. 
Syn.—Glauconome, Gray, 1829 (not Goldfuss, 1826). 
Distr.—16 sp. Hmbouchures of rivers ; China, Philippines, 
Borneo, India. Fossil, 2 sp. Tertiary ; "Europe. G. rugosa, 
Reeve (cxii, 3-5). 
Shell oblong, thin; epidermis dark, greenish; ligament exter- 
nal; hinge with three teeth in each valve, one of them bifid ; 
pallial sinus very deep and angular. 
Animal with a rather small, linguiform foot; pedal opening 
moderate; siphons very long, united, projecting far into the 
branchial cavity when retracted, their ends separate and diver- 
ging; palpi large, sickle-shaped ; gills long, rounded in front, the 
outer shortest. 
TANYSIPHON, Benson, 1855. Siphons united to the end; hinge 
with three teeth in the right and two in the left valve; pallial 
sinus very deep. Calcutta, buried in mud at extreme low-water. 
G. rivalis, Benson (exii, im 2 a 
Sunorper INTEGRIPALLIATA. 
Siphons short, not retractile; the pallial impressions simple, 
usually without siphonal sinus. 
