ALN OD OEN, 
Pirate XXXVII. 
Species 152. (Mus. Brit.) 
ANODON GIGANTEUS. An. testd magna, inflata, levigato- 
undulata, ovato-subtrigona, olivaceo-viridi, fusco et 
viridi fasciald ; latere antico amplo, rotundo, alto, 
margine elevato, umbonibus amplis ; latere postico 
producto, subattenuato, subacuminato, margine dor- 
sali declivi, ventrali, sinuato et surstim acclivi. 
THE Gigantic Anopon. Shell large, inflated, smoothly 
undulated, ovately subtrigonal, olive green, banded 
with brown anterior side full, 
round, high, margin elevated, umboes full; pos- 
terior side produced, rather attenuated, subacumi- 
nated, dorsal margin sloped, ventral sinuated and 
and green, 
sloped upward. 
Lea. Obs. on Unio, vol. ii. pl. 1, f. 2. 
Hab. Port Gibson. 
The Brazilian shell figured as species 18, is given 
under this name by error, owing to the specimen being 
so named in the Cumingian collection. Our species 18 
must be referred to Anodon Trapezialis, Lamarck, with 
which it fairly enough agrees. 
Species 153. (Mus. Lea.) Copied. 
ANODON SIMPSONIANUS. 
parva, tenui, subcompressd, 
An, testa inequaliter ellipticd, 
fumeo-fuscd, intis 
ceruleo-alba ; latere antico angusto, breviusculo, 
rotundo ; umbonibus prominulis, ad apices undu- 
latis, margine ventrali cequaliter convexo ; latere 
postico subexpanso, subangulato. 
Simpson’s Anopon. Shell unequally elliptical, small, 
thin, suabeompressed, smoky, brown, bluish white, 
within; anterior side narrow, rather short, rounded; 
umboes rather prominent, undulated at the apices, 
ventral margin equally convex; posterior side a 
little expanded, slightly angular. 
| Lea. Obs. on Unio, vol. viii. p. 34, pl. 32, f. 281. 
| Hab. Fort Rae, Great Slave Lake, Arctic America. 
Species 154. (Mus. Lea.) Copied, 
ANODON TORTILIS. 
sublevigatd, minute undulatim striata, olivaced, 
intus subceeruleo ; 
An. testd subtrigond, parvd, tenui, 
latere antico angusto, margine 
dorsali declivi ; umbonibus parvis, minute lineatis, 
margine ventrali rectiusculo ; latere postico expanso, 
laté truncato, margine dorsali subelevato, recto. 
WREATHED ANopon. Shell subtrigonal, small, thin, 
rather 
bluish 
margin 
THE 
smooth, minutely wave-striated, olive 
side dorsal 
sloped, umboes small, minutely lineated, 
within; anterior narrow, 
ventral margin rather straight; posterior side 
expanded, widely truncated, dorsal margin a little 
elevated, straight. 
Lea. Obs. on Unio, vol. v. p. 47, pl. 27, f. 54. 
Hab. Cartagena, South America. 
The character of the epidermis which induced Mr. 
Lea to name this shell Anodon tortilis is not very clearly 
expressed in the figure, but the reference is probably 

to a semispiral undulation in the strie of growth. 
June, 1870. 
