86 Couthouy's New Species of Mollusca 
The first specimen obtained was considerably mace- 
rated, and in that condition, the external coat being lost, 
and the central areas only, conspicuous, had very much 
the aspect of a Chitonellus. It evidently forms one of 
the connecting links between the two genera. The 
elastic integument with which it is covered, and the 
rounded form of the valves, must render the shell much 
more flexible and consequently afford the animal far 
greater freedom of motion, especially in turning, than is 
possessed by the generality of Chitons. 
No single specimen was procured, entirely perfect, but 
as the deficiencies existing in some were supplied by 
others, the description may be relied upon for accuracy. 
Indeed a description from a perfect specimen alone, 
would, from the peculiar organization of the shell, be 
very imperfect, many of the characters being only visi- 
ble when the external coating is effaced, as was the 
case with most of my specimens. 
I have named this singular species in honor of George 
B. Emerson, Esq., President of the Boston Society of 
Natural History, as a token of affectionate remembrance 
on the part of his former pupil. 
PATELLA CANDIDA. 
P. testà parvulá, ovali, sub-diaphanà, candida, concentricé striata, 
costis scabris, exiguis, radiantibus; intüs nitidà. 
Long. seven twentieths, lat. four twentieths, alt. two 
twentieths, of an inch. 
Habitat Mass. Bay. 
Cabinet of Bost. Soc. Nat. History. 
Description. Shell small, thin, oval, moderately 
x 
