944 JETHERIID A. 
Mycerorus, d’Orbigny, 1835. 
Etym.— Mukes, a mushroom ; pous, the foot. 
Distr.—3 sp. River Parana, Corrientes; River Amazon, 
Bolivia. MM. soleniformis, Orb. (exxv, 11). 
Shell elongated, subecylindrical, gaping in front; margins sub- 
parallel, hinge edentulous. 
Animal with an elongated, cylindrical foot, expanded into a 
disk at the end; mantle open; gills equal; palpi short. 
SOLENATA, Conrad. Elongated, thin, gaping anteriorly, hinge 
with a long, acicular lateral tooth in each valve, slightly 
developed. Recent; Oriental. J. emarginatus, Lea (cxxv, 
12.13). 
( Atheriacea.) 
Faminy ZETHERIID 4. 
Shell irregular, inequivalve, attached, pearly within. Animal 
without foot. These may be likened to oysters, which they 
much resemble in the general appearance of the shell. The 
family includes three somewhat similar genera, one of which is 
African, the others South American. 
ANTHERIA, Lamarck, 1808. 
Etym.—Attherios, aérial. Fresh-water oyster. 
Distr.—4 sp. River Nile, from first cataracts to Fazool; River 
Senegal. 4. Cailliaudi, Fer. (cxxiv, 6). 
Shell irregular, inequivalve; attached by the umbo and tubular 
processes of one of the valves, usually the left; epidermis thick, 
olive; interior pearly, blistered (as if with air-bubbles) ; hinge 
edentulous; ligament external, with a conspicuous area and 
groove in the fixed valve; two adductor impressions, the anterior 
very long and irregular; pallial line simple. 
Animal with the mantle-lobes open; body large, oblong, pro- 
jecting backwards; no trace of a foot; palpi large, semioval; 
gills subequal, plaited, united posteriorly, and to the body and 
mantle. 
Mouttertia, Férussac, 1823. 
Etym.—Dedicated to Otto Frid. Miller, author of the “ Zoologia 
Danica.” Syn.—Acostea, d’Orbigny, 1851. 
Distr.—River Magdalena, near Bogota, New Grenada. WM. 
Guaduasiana, Orb. (exxv, 14, 15). 
Shell, when young, free, equivalve, Anodon-shaped, with a 
long and prominent ligament, and two adductor impressions ; 
adult irregular, inequivalve, attached by the right valve; umbones 
elongated, progressively filled up with shell, and forming an 
irregular “talon” in front of the fixed valve; epidermis thick ; 
ligament in a marginal groove; interior pearly, muscular impres- 
sions single, posterior. 
