ANODON. 
Puate XVI. 
Species 57. (Maus. Brit.) 
ANopON RxoTIcus. An. testd magna, rhomboideo-subcu- 
neatd, gibba, levigatd, epidermide crassa, pallide stra- 
mined, postice viridi radiatin pictd; latere postico 
validé et perobliqué angulato, gibbo, lato, margine | 
dorsali recto, elevato, margine laterali perobliquo, ter- 
mino acuminatim producto, margine ventrali recto ; 
latere antico brevi, subacuminatim rotundo, umbonibus 
inflatis, levigatis. 
Tur Exovre ANopon. Shell large, rhomboid-subcu- 
neate, gibbous, smooth, epidermis thick, pale straw, 
painted with green rays at the back; posterior side 
strongly and very obliquely angular, gibbous, wide, 
with dorsal margin straight, elevated, lateral mar- 
gin very oblique, acuminately produced at the end, 
ventral margin straight; anterior side short, subacu- 
minately rounded, umboes inflated, smooth. 
Gray, in Mus. Brit. 
Hab. Rio de la Plata. 
This shell must not be confounded with the Lpidina 
evotica, which is much narrower and more elongated. 


Species 58. (Mus. Brit.) 
Anopon Nopatatensis. An. testd valde inflata, magni, 
rotundatim ovata, tenui, utringue hianti, concentricé 
leviter rugatd, viridi-grisescenti, obscure radiata, 
intus vivide iridescenti; latere postico perobliqué ob- 
scur> biangulato, acuminato, margine dorsali subde- 
elivi, margine laterali subexcavato, termino elevato, 
margine ventrali ad terminum valde sursum acclivi, 
ad medium subcontracto ; latere antico semirotundo, 
umbonibus magnis, valde inflatis. 
Tue Noratara Anopon. Shell much inflated, large, 
roundly ovate, thin, gaping on both sides, concen- 
trically slightly wrinkled, greyish-green, obscurely 
rayed, brilliantly pearly within; posterior side very 
obliquely obscurely biangular, acuminated, dorsal 
margin slightly sloped, lateral margin a little exca- 
vated, with the end raised, ventral margin much 
sloped upwards at the end, a little contracted in the 
middle; anterior side half-rounded, umboes large, 
much inflated. 
SOWERBY. 
Hab. River Nopalata, Mexico. 
Remarkable for the roundly ovate amplitude of its form. 

September, 1867. 
