57 
ting from the umbo of the left valve towards the ventral margin, but 
none have them in such numbers, or so distinctly marked, as in the 
present small species. Here they are about ten in number, and with 
the great disparity of the valves, will readily distinguish the species. 
Corsuta routa. Corb. testa. oblongd, ventricosd, tenui, albidd, 
obsoleté sulcatd, antic rotundatd, postice ab umbonibus subangu- 
laté ; valvis feré equalibus, dextre margine ventrali acutd, sub- 
producta ; umbonibus @qualibus, levigatis, rectis. Long. 34; 
lat. 2; alt. 24 lin. 
Hab. Sorsogon, province of Albay, Luzon, Philippine Islands. 
Cab. Cuming. 
Corsuta quaprata. Corb. testd quadratd, albidd, tenui, levigatd, 
antice rotundato-truncatd, postice rotundato-angulata, abbreviatd ; 
valvarum marginibus ventralibus tenuibus ; umbonibus obliquis, an- 
ticis ; dentibus parvis, gracilibus. Long. 6; lat. ; alt. 5 lin. 
Hab. ? 
Cab. Metcalfe. 
Corsuta opgsa. Corb. testd ovata, tenui, ventricosd, pallida, striatd, 
anticé rotundatd, posiice ad extremitatem truncata, ab umbonibus 
acute angulatd ; valvarum marginibus ventralibus inclausis, gib- 
bosis ; umbonibus rectis, levigatis. Long. 3; lat. 2; alt. 2 lin. 
Hab. The west coast of America, between 8° 57! and 21° 32! north 
latitude, in from twenty-two to thirty-three fathoms, mud; namely, 
Panama, coast of Veragua, and San Blas. 
Cab. Belcher. 
Corsuna speciosa. Corb. testd ovato-trigond, antice rotundatd, 
postice excavate angulatd, albidd, sanguinea, dense multiradiatd ; 
valvis valde inequalibus, marginibus ventralibus inclausis, dextrd 
rotundatd, sulcatd, sinistrd subplanulatd, striatd; umbonibus rectis, 
subplanulatis ; intds albidd. Long. 9; lat. 5; alt. 7 lin. 
C. radiata, Sowerby, Proc. Zool. Society, p. 36, 1833. 
Hab. Panama; from six fathoms, mud. Gulf of Nicoya, Central 
America. 
Cab. Belcher et Cuming. 
This shell has been described as C. radiata, Sow., a name pre- 
viously assigned by M. Deshayes to a fossil species. The description 
also was drawn up from such an indifferent shell, that it was almost 
by accident I discovered it was to apply to my specimens. I have 
therefore been under the necessity of recording a new description. 
CorsuLa mopEsTa. Corb. testd ovato-trigond, complanatd, pal- 
lidd, radiata, profunde sulcatd, antice rotundatd, postice ad extre- 
mitatem truncatd, ab umbonibus angulatd ; valvarum marginibus 
ventralibus inclausis; umbonibus parvis, subequalibus, roseis ; 
*intis rosed. Long. 7; lat. 34; alt. 5 lin. 
Hab. Straits of Macassar ; from seven fathoms, coarse sand. Ticao, 
Philippine Islands ; from eight fathoms, sandy mud. The Macassar 
specimens are of a dwarf size. 
Cab. Belcher et Cuming. 
