804 BULLETIN UNITED STATES GEOLOGICAL SURVEY, 



margin; a double row of spines on the under surtace; the anterior ones 

 and those on the outer row are the largest, those on the inner row smaller 

 and of a greater number. 



Third pair of legs hooked. First pair of abdominal legs long, deeply 

 bifid ; external part longer, and tapering to an acute point ; internal part 

 broadly compressed. 



Closely allied to Caynharus virilis Hagen, but presents the following 

 points of difference, which were observed to hold good in all the twenty- 

 two specimens collected from one locality when compared with twenty- 

 three specimens of C. virilis from the Souris or Mouse River: — Body 

 more cylindrical, less depressed ; sides less inflated ; in fact, the general 

 appearance of the species, in all its parts, is more slender and less robust 

 |;han 0. virilis. Eostrum narrower, longer, more deeply excavated 

 •above; anterior portion of the rostrum in advance of the lateral teeth 

 narrower and more produced, longer than its transverse measurement 

 at the base. In C. virilis the anterior portion of the rostrum is not longer 

 than broad at its base between lateral teeth. Point of the rostrum, 

 lateral teeth, the spines on the ridge at the base of the rostrum, and 

 those on the sides of the carapace, are long, acute, and more prominent 

 than in C. virilis; in the latter, the spines in these situations, except on 

 sides of carapace, are short and obtuse. Finally, the hands of the an- 

 terior pair are longer and more slender, and the internal part of the 

 first abdominal legs is more broadly compressed. 



Length of body 2.7 inches; external antennae 2.4 inches; anterior 

 pair of legs 2.1 inches. 



Locality, Red River of the North. Obtained from the stomach of a 

 Pelican shot in May, 1873, on the Red River near Pembina. The bird 

 was sick and unable to fly ; the Crawfish must, therefore, have been 

 secured in this locality. Collected by Dr. KUiott Coues, U. S. A., then 

 Surgeon and Naturalist of the United States Northern Boundary Sur- 

 vey, to whom the species is dedicated. 



A second species of the same genus was also taken by Dr. Coues in 

 Dakota : — • 



CAMBA.RUS VIRILIS, Hagen. ■ 



Canibarm virilis, Hagen, Ulustr. Catal. Mus. Comp. Zoology, No. 3; Mono- 

 graph of the North American Astacidie, p. 63, pi, 1, flgs. '23-26 ; pL 2, figs. 

 128-132 ; pi. 3, fig. 155 ; pi. 8. 



Locality, Souris or Mouse River, Dakota. 



The following observations on the color of this Crawfish were fur- 

 nished by Dr. Coues: — "In bed of stream among stones, in shallow 

 water, very abundant. Carapace variegated with lighter and darker 

 shades of brown: tail segment darker and more uniform brown, with 

 large symmetrical dark brown spots, one on each side. Claws green, 

 speckled with darker, with the protuberances j^ellow and reddish ; other 

 legs paler greenish. Below, including under side of the claws, green- 

 ish-white, the claws speckled with dark spots. Antennae rich brown." 



