108 A REVISION OF THE ASTACID^. 



Female. — Hand small, fingers not gaping, ciliated within ; sternum 

 between fourth pair of legs plane ; annulus ventralis bilaterally symmetrical, 

 anterior border bituberculate, postei'ior border unituberculate, transverse 

 fossa deep, recurved at each end. 



Measurements of male, form I. — Length of body, 49 mm. Length of 

 carapace, 25 mm. Length of rostrum, 6 mm. Length fi'om end of rostrum 

 to cervical groove, 15.5 mm. Length from cervical groove to hind border 

 of carapace, 9.5 mm. Width of areola, 2 mm. Length of abdomen, 25 nnn. 

 Length of chela, 23.5 mm. Length of internal margin of hand, 9.5 mm. 

 Breadth of chela, 11.5 mm. Length of movable finger, 14 mm. 



Two specimens, first form of male and female, in the Museum of Compar- 

 ative Zoologj^ from Irondale, Mo. 



This species has the general form of body, rostrum, and chelae of the 

 C. Bartonii group, together with the male abdominal appendages of the 

 C. affiiiis group. These appendages have a projecting shoulder at the base 

 of the rami, on the anterior edge, as in C. rusticus, C. PiUnanii, etc. C. im- 

 nmnis and C 3£ississippiensis, belonging to the C. affinis group, also have the 

 rostrum devoid of lateral spines, but in general habit of body they do not 

 resemble C. Bartonii and its allies, as is the, case with the present species. 



47. Cambarus rusticus. 



Plate IX. fiffs. 8, 8 , 8 a, 8 a (fli'st abdominal appendages of male). 



Cambarus rusticus, Gikabd, Proc. Acad. Nat. Sci. Pliila., VI. 88, 1852. 



Cambarus rusticus, Hagen, 111. Cat. Mus. Comp. Zool., No. III. p. 71, PI. I. figs. 80-83, PI, III. fig. 161, 



1870. 

 Cambarus placidus, Hagen, op. cit., p. 65, PI. "I. figs. 76-79, PI. III. fig. 158, 1870. 

 Cambarus juvenilis, Hagen, op. cit. p. 66, PI. I. figs. 29-33, PI. 111. fig. 157, 1870. 

 Cambarus rusticus. Smith, Hep. U. S. Coinni. Fisli aud Fisheries for 1873 and 1873, p. 639, 1874. (After 



Hagen. No description.) 

 Camljarus placidus. Smith, op. cit.. p. 638, 1874. (After Hagen. No description.) 

 CamlMtrus juvenilis. Smith, op. cit., p. 38, 1874. (After Hagen. No description.) 

 Cambarus Jf'iscoiisiiieiisis, Buxdy, Bull 111. Mus. Nat Hist., No. I. p. 4, 1876. — Trans. Wis. Acad. Sci., V. 



181, 1882. — Geol Wis., Surv. 1S73-1879. I. 402, 18S3. 

 Cambancs placidus, Fobbks, Bull. 111. Mus. Nat. Hist., No. 1. pp. 4, 19, 1876. (After Hagen.) 

 Cambarus Wiscoimiwnsis, Forbes, op. cit., p. 19. (.\fter Bundy.) 

 Cambarus rusticus, Bundy, Trans. Wis. Acad. Sci., V. 181, 1882. — Geol. Wis., Surv. 1873-1879, I. 402, 



1883. (Not described.) 

 Cambarus placidus, Bundy, Trans. Wis. Acad. Sci., V. 181, 18S2. (Not described.) 

 Cambarus rusticus, F.axon, Proc. Amer. Acad. Arts and Sci., XX. 148, 1884. 



Male, form L — Rostrum long, narrow, concave on tlie sides, excavated, 

 margins thickened, dotted-lined, divergent at the base ; acumen of moderate 



