ASTACID^. 45 



rated .since the epistoma is truncated at the tip. C. ClarJdi differs in 

 Inning the thorax strongly tuberculated, the areola linear or none; the 

 base of the rostrum with two linear elevations joined in obtuse angle; 

 the second article of the exterior antenna}, with the teeth shorter than 

 its tubercle (as long as in C. Blandingii and very acute) ; the lamina 

 is more enlarged at the tip ; the hands broader, shorter, the fingers 

 more arcuated and deflected, more tuberculated (one tnbercule on 

 the inside of the external finger in the middle in 0. Blandingii) ; the 

 abdominal legs differ also. C. troglodytes differs by the same characters. 



C. acutus Gir. is very near in the shape and sculpture of the rostrum 

 and epistoma, but the lamina is much larger at the tip ; the teeth of 

 flu 1 second article are shorter than the tubercle, the hands broader and 

 shorter, the abdominal legs different. I have seen some hundred males 

 of all sizes, but never a male with the abdominal legs analogous to 

 C. Blandingii. The body is more tuberculated. 



The females from Essex, New Jersey, quoted under C. acutus (but it 

 is always difficult to identify females with males) are more similar, the 

 body is not very strongly tuberculated, the lateral spine is evident, the 

 lamina smaller at the tip. 



C. LeContci is very near, but the abdominal legs are different; the 

 shape of the hand is most similar, but the fingers are shorter and 

 straight; the rostrum strongly dentated at the tip, the areola broad. 

 The typical specimen of C. Blandingii is very well developed and it does 

 not seem to me to be an abnormal specimen of C. acutus with abnormal 

 hands, abdominal legs, and lamina. I cannot help regarding it a good 

 species, perhaps (?) identical with the New Jersey females described 

 provisionally as C. acutus. 



It is not impossible that C. Blandingii LeConte, 1. c. p. 400 (Georgia? et 

 Carolina 1 regionibus intermediis), is this species, but in this the linea 

 ordinaria is sulcated as in C. troglodytes, and not sulcated m LeConte' s 

 species. Erichson gives but a copy from Mr. Harlan's description. 



C. Blandingii Gir., 1. c. p. 91, without description, is probably C. 

 troglodytes, which the Museum possesses from the same locality, Sum- 

 merville, South Carolina, given by Mr. Girard. (Vide C. Lecontci.) 



5. Cambarus Fallax Hagen. 



Figures on PI. I. 

 First abdominal leg of the male : 



first form, fig. 103 in front, fig. 104 outside, 

 second form, fig. 105 inside. 



Mas. Rostro elongato triangulari, hevi, excavato ; acumine suba- 

 cute, ciliato, spina utrinque acuta; cretis basalibus validis, parallelis, 

 extus vix sidcatis, apice acutis. Antennis gracilibus, corpore breviori- 

 bus, articulis' duobus basalibus dente acuto externo ; antennis intends 



