90 A REVISION OF THE ASTACIDA. 
curved, costate above; the two fingers are furnished with blunt tubercles 
on their opposed margins, which touch one another only at their tips. Car- 
pus with a strong inner tooth. Third pair of legs hooked. First pair of 
abdominal appendages stout, bifid; rami short, acute, outer one with its tip 
turned outwards, inner one with its tip turned inwards ; tips brown, horny. 
Male, form II.— The fingers are less gaping, the hooks on third pair of 
legs small, the first pair of abdominal appendages are bifid for a less distance 
from the tip, the rami are swollen, without horny tips; these appendages 
may or may not be articulated near the base. 
Female. — Chela like that of the male, form HW. Annulus ventralis with 
anterior border depressed, posterior border elevated, tuberculate, tubercle 
divided longitudinally by a sinuous furrow. 
‘Known Localities. — Indiana: New Albany. Kentucky (Bundy). 
I have seen two of the types of this species, male form I. and female, 
in the collection of the Peabody Academy of Science, Salem, Mass. Dr. 
Sloan has also sent me specimens taken at the same time with those sent 
to Bundy for description, and there are specimens from the same source 
in the collections of the Boston Society of Natural History, the Peabody 
Museum of Yale College, and Butler University, Irvington, Ind. 
Dr. Sloan writes me that this is the common species in running streams 
at New Albany, while C. Bartonii is the form found in still waters. Accord- 
ing to the same gentleman, as quoted by Bundy, this is a burrowing species. 
“‘ He commences on the bank of the stream, burrows below the bed, and has 
an opening two or more feet out in the stream, where he sits watching for 
anything that may turn up, with a safe retreat.” 
C. Sloanii closely resembles C. propinquus, var. obscura, in general appear- 
ance, but may be at once distinguished by the male appendages and the 
annulus ventralis of the female. In the latter species the anterior border of 
the annulus is prominently bituberculate, whereas in C. Sfoami the anterior 
rim is sunk below the level of the sternum in front of it. 
The largest specimen seen by Bundy measured 3} inches in length. The 
largest I have seen, a female, is a little less than three inches long. 
