450 NO Si GeAs 
They are disposed as in M. hamatus, but are much larger, as 
in M. demissus. Another species, probably from New Holland, is 
grooved much like it, but is larger, and differs in its form. 
Figures 565, 565 a, lateral and dorsal views of the shell. 
Myritus aueosus (Gould). 
T. transversa, subcylindrica, elliptico-triangularis, valde corrosa, epider- 
mide tenut, intense smaragdino induta ; margine dorsah angulato, 
postice ad marginem ventralem rectum parallelo ; latere postico rotun- 
dato; fustiqgio umbonali tumido, obtuso ; cardine edentulo: intus 
punicea. 
Mytilus algosus, Goutp ; Proceed. Boston Soc. Nat. Hist., iii., 344 
Dec. 1850. Expedition Shells, 94. 
SHELL elongated, spatulate; upper half triangular, lower semi- 
oval; dorsal margin obscurely angular, ventral margin nearly straight ; 
fissure for byssus very small; valves semi-cylindrical ; apex on a level 
with the base; surface generally eroded; marginal portion covered 
with a smooth, shining, thick, invisible-green epidermis; rather com- 
pressed at tip; hinge toothless; interior clouded slaty and claret-red. 
Length an inch and three-fourths; height and width five-eighths 
of an inch. 
Inhabits the Feejee Islands. 
The slender cylindrical form, very dark green epidermis, and inte- 
rior coloration, are good diagnostic characters. 
Figure 566, lateral view of the shell, exterior and interior; 566 a, 
dorsal view. 
MyviLus TRossuLus ((Govid ). 
T. parva, elongata, sub-arcuata, nitida, coracina, subtus cerulea ; umbo- 
