Zoological Society. 59 
incurvatis ; pube pland ; dentibus lateralibus approximatis. Long. 
1°30; lat. 1°60 pol. 
Hab. Tumbez, Peru (Cuming). 
Closely resembling dentiferus, but not provided with the charac- 
teristic tooth, much stronger and more triangular, and with its ven- 
tral edge more arcuated, and its front extremity more attenuated. 
The front dorsal edge appears retuse (which it is not in reality), from 
the lateral projection of the swollen beaks. The lower margin is 
stained with violet anteriorly. 
Donax Navicuta. Don. testd elongato-trigond, crassa, subventri- 
cosd, nitidd, subinequilaterali, sublevigatd (striis radiantibus 
tantum in medio perspicuis), albd, epidermide flavd indutd, prope 
marginem dorsalem utrinque brunneo-purpurascente strigatd ; mar- 
gine ventrali in medio ventricoso, intus crenato ; dorsali antice 
subrecto et subdeclivi, postice incurvato et declivi; ared posticd 
levi, subconcavd ; latere antico longiore, angustato, ad extremitatem 
rotundato ; postico cuneiformi, ad extremitatem obtuso ; ligamento 
minimo ; costd umbonali obtusd ; superficie internd albidd, utrinque 
superne purpured ; dentibus lateralibus maxime approzximatis. 
Long. 0°40; lat. 0-90 poll. 
Hab. Gulf of Nicoya, Central America (Cuming). 
Allied to californiensis, but more triangular. 
Dowax eGracitis. Don. testd elongatd, angustd, nitidd, valde in- 
equilaterali, compressa, sublevigaid, albidd aut pallide violaceo- 
rufescente, epidermide lutescente indutd ; margine ventrali convexo 
aut subarcuato, haud flecuoso, intus crenulato ; dorsali magis mi- 
nusve livido, utringue subrecto, antice viv paululim declivi, postice 
valde declivi; latere antico producto, attenuato, ad extremitatem 
rotundato, postico acuminato-cuneiformi ; ligamento minimo ; ared 
posticd levi, obtusissima ; costd umbonali obtusd ; superficie interna 
purpurascente ; dentibus lateralibus perspicuis, approximatis. 
Var. b. Testa aibidd, radiis paucis livido-rufescentibus ornatd. 
Var. ce. Testd rufescente aut lividd. 
Long. 0°40; lat. 1 poll. 
Hab. Bay of Guayaquil. Var. 6. Chiriqui. Var. ec. Bay of Carac- 
cas (Cuming). 
Allied to Owenii, but with the margin crenulated. 
Donax sorpipus. Don. testa abbreviato-cuneiformi, converd, niti- 
diusculd, solidd, valdé inequilaterali, striis exilibus simplicibus 
confertim radiatd, sordide albidd ; lineis elevatis obliquis subcon- 
centricis, partem superiorem et levigatam teste postice asperanti- 
bus ; margine ventrali crenulato, medio arcuato ; dorsali antico, 
declivi et subrecto ; postico subrecto et valde declivi ; latere antico 
altenuato ; postico brevi et inferne (in adultis etiam superne) obtuse 
angulato ; pube fortiter et confertim rugis subdecussatis concentricé 
exaratd ; costd umbonali subangulatd ; superficie internd albidd, 
purpureo infectd ; dentibus lateralibus approvimatis, antico per- 
magno. Long. 0°70; lat. 1 poll. 
Hab. Cape of Good Hope. Mus. Brit., Cuming. 
