78 ASTACIDiE. 



son. It is a young male of the second form, with the abdominal legs 

 articulated. The animal is identical with C Barimii, and the shape 

 of the epistoma forbids us to regard it as a young C. htimanus. The 

 external lamina of the postabdomen has the inner third of its margin 

 not denticulated. A diy male specimen from Virginia, C moiitaims, 

 Acad. Philad., is identical with the foregoing, the abdominal legs ex- 

 actly resemble those of C. Bartonii. In the Cambridge Museum there 

 is a jar with alcoholic specimens labelled, Isle of Pico, Azores, presented 

 by Mrs. Dabney. It contains one Alphciis and three C. BurtonU. It 

 seems very doubtful at present that these Camhari are from the Azores. 

 The types in the Cambridge Museum of A. Burtomi Gibbes, mentioned 

 in his Fauna of South Carolina, belong to C. Mimanns. The types of 

 C. Bartonii in the Mus. Acad. Philadelphia, from Pennsylvania and Pitts- 

 burg, also determined by Mr. L. R. Gibbes, are C uffiim Say. 



A female type of C. lowjulm Gir., Proc. Acad. Philad., T. 6, p. 90, com- 

 municated by Professor Stimpson, is from the Middle States ; it differs 

 from C Bartonii in having its hands smooth, very large, and apparently 

 deformed. The fingers are small and unusually far separated at the 

 base. In the space between them is a large bunch of hairs. I have 

 not found such a bunch of hairs in any specimen of C. Bartonii ; per- 

 haps there was more room for the growth of these hairs in this de- 

 formed specimen. But I should remark that specimens of C. Bartonii, 

 with the fingers about as widely separated, are destitute of any such 

 tufts. I have sometimes found hairs in this place, but never so many 

 in C. htimanus. Nevertheless, the other characters show that it must 

 be C. Bartonii or a new species. I think it is C. Bartonii. 



C. Bartonii is the most variable species ; as yet I cannot find stable 

 and constant characters for dividing them into three or four species, as 

 Mr. Girard has done. The rostrum is often nearly quadrangular, with 

 a little tooth in the middle of its front border, and varies in being more 

 elongated, more attenuated before, with the angles more or less rounded 

 and the apical tooth longer or shorter, l)roader or narrower. The lamina 

 of the antenna? varies in breadth, principally in front, and in the length 

 of the apical spine. The epistoma is often triangular, acute, often more 

 rounded laterally, sometimes more obtuse at the tip and nearly trun- 

 cated in front. The dorsal areola varies in specimens from the same 

 locality (Cincinnati from {--^ to /„ inches). The form of the hand is 

 exceedingly variable, the fingers being often broadly separated at their 

 base, frequently nearly contiguous. 



The type of C. montanus does not differ from the typical form. The 

 length of the antennse quoted by Girard is variable. One male from 

 Cincinnati, with the most quadrangular rostrum, has the antennaj oven 

 longer than the body. 



I have seen more than one hundred specimens from Lake Superior, 



