98 Mr. S. Stutehbury on two new generu of Mollusca. 
In general contour, this shell has so greata similitude to Chama, that 
without opening it there would be no hesitation in pronouncing it of that 
genus, belonging to Lamarck’s division, ‘‘ Crochets tournant de droit a 
** gauche.’’ Its internal differences.are given in the generic description. 
The species I characterise as follows :— 
CLEIDOTHZRUS CHAMOIDES. 
Tas. Supp. xxi. f. 5, 6,7, 8. 
C. testd involutd, rufa, interne subviridi sub-margaritaced ; valvd 
dextrd majore profundd, latere antico adherente; latere convexo 
clavicule sulcato. 
Shell involute, brownish red, internally of a greenish pearly lustre, 
attached by the anterior side of the right valve, which is of great depth; 
left valve but slightly convex ; the clavicular appendage with a groove on 
the convex side. 
My specimens being destitute of colour, the figure has been taken by 
G. B. Sowerby, jun., from one in his father’s collection, which he found 
among the stores of thelate Mr. Humphreys, but which, not having the clavi- 
cular appendage, had been laid aside, until more perfect specimens should 
decide its true characters. Mine were found attached to sand-stone rocks 
by T. Young, Esq., R. N., together with an Aspergillum (perhaps agglu- 
timans of Lamarck), some Chame, &c. while searching near the entrance 
of Port Jackson, pointed out to him as the spot where I discovered, in 
1286, the first living Clavagelle. 
The five following shells bear so close an analogy to Myochama, that 
believing the four last'to be inedited, I am induced to give specific de- 
scriptions of them, adding them to the genus Anatina. I must, however, 
premise, that the spoon-shaped teeth mentioned by Lamarck are absent 
in each, but they possess the moveable appendage to the hinge, found in 
most, if not all the shells placed in that genus by him. 
entirely inapplicable that I hesitate not to retain the appellation of Cleido- 
therus, by which I had designated it. There is nothing in the shell to con- 
nect it with Ostreu. 
