I LMBAE.US. 43 



an opportunity to examine Cope's type. It is a male, form 11., with the 

 first pair of abdominal appendages not articulated, a condition often found in 

 the second form males of this species. Alter an examination of this speci- 

 men, I can indorse the opinion of Hagen (Amer. Nat., Aug., 1872) and Pack- 

 ard i Fifth Ann. Rep. Peabody Acad. Sci., for 1872), expressed before seeing 

 the specimen, that the variation is not of specific value. All the specimens 

 which I have seen from the Indiana caves, amounting to six in number, 

 belong to this form. But the same form also conies from the Mammoth and 

 neighboring caves in Kentucky. In a gigantic female in the Museum of 

 Comparative Zoology (No. 3417, collected in Mammoth Cave by F. W. 

 Putnam), the peculiarities of Cope's form are intensified. The point of the 

 rostrum does not reach the distal end of the peduncle of the antennule, and 

 hardly attains the proximal end of the distal segment of the peduncle of 

 the antenna.* The lateral rostral spines are reduced to salient angles. The 

 post-orbital ridges are destitute of spines, as in C. Barlonii. The antenna] 

 scales reach but to the proximal end of the terminal segment of the peduncle 

 of the antenna. The lateral spinules of the carapace are represented by 

 granular tubercles. The spines of the meros of the cheliped are short and 

 tooth-like ; those on the upper surface are blunt, those beneath are irregularly 

 disposed, without the clear biserial order seen in the typical form, and also in 

 Cope's type of 0. inermis. The hands are broad, flattened, and tuberculate. 



In this specimen, moreover, the anterior process of the epistoma is trun- 

 cated in front. The dimensions are subjoined. Length of body, 93 nun. ; 

 of carapace, 111 mm. ; of rostrum (from level of post-orbital spines to tip), 

 9 min.; of abdomen, 49 mm.; from tip of rostrum to cervical groove, 26 

 mm.; from cervical groove to posterior margin of carapace, 2(1 nun. Length 

 of cheliped. Si mm.; of chela, 43 mm.; of antenna, 80 mm.; of antennal 

 scale, 8 mm. 



The other blind Cambarus from the United States (C. hamnktus from 

 Nickajack Cave, Tenn.) resembles C. pellucidus superficially, but belongs to 

 Group 111., with hooks only on the third pair of legs in the male. The first 

 pair of abdominal appendages are very different from those of C. pellucidus, 

 being formed after the pattern of those organs in C. Bartom. The annulus 

 ventralis of the female is also different. 



A small specimen of c. pellucidus was found in ajar containing ('. Pulnami 

 from Green Liver, near the Mammoth Cave, collected by Mr. F. W. Putnam. 



* [n the typical form of i i rostrum equals or exceeds in length the peduncle of I 



