304 MR. BRODERIP ON THE GENUS CHAMA. 
points it agrees with Lamarck’s Chama florida; but he describes the margin of that 
shell as entire, whereas the margin of Chama Pacifica is strongly crenated. 
Mr. Cuming’s specimens were obtained by diving. They were attached to Avicule 
(Meleagrine, Lam., Margarite, Leach,) at a depth ranging from three to seven 
fathoms. 
Many shells of this species were brought to this country some years ago, from the 
Pear] Islands, by Mr. Samuel Stutchbury. 
CHAMA IMBRICATA. 
Tab. XXXIX. Fig. 2. 
Chama testé lamellosé, squamis imbricatd, albidd purpureo-fusco varia ; valvd superiore 
subdepressd, sublobatd, sinu ab umbone usque ad limbum currente ; intus albidd, limbo 
integro sepissimé nigro-purpureo. 
Hab. in Oceano Pacifico. (Lord Hood’s Island, Pearl Islands.) 
This grows to a large size, and was obtained by diving by Mr. Cuming, attached to 
Avicule at a depth ranging from three to seven fathoms. There is generally a purple 
spot at the tip of the wmbo of the upper valve. 
This also was brought home in considerable numbers by Mr. Samuel Stutchbury from 
the Pearl Islands, and I have more than once been inclined to think that it may be a 
variety of Chama Pacifica. But the internal edge of the former is always crenated, that 
of the latter, except towards the hinge-border, is smooth, and the depressed line of its 
upper valve is very strongly marked, however the external shape may vary. 
Var. «. Nana, castanea albo strigata, intus alba. 
Tab. XXXIX. Fig. 3. 
Hab. ad Insulas Gallapagos dictas. 
The examination of an extensive series has led me to the conclusion that this dwarf, 
and at first sight widely differing, shell, is only a variety of Chama imbricata. The pur- 
ple brown is changed into chestnut striped with white ; and hardly any scales are to be 
found on its wrinkled surface except the double series which crown the ridge on each 
side of the depressed line, and sometimes a series or two on the affixed valve. This 
depressed line is not nearly so well marked as it is in the large variety, but it is to be 
observed on most of the specimens: some are absolutely without imbrications. 
A figure of one of these turning from right to left (some specimens turn from left 
to right) is given. 
This variety was found by Mr. Cuming attached to rocks and stones at low water. 

