108 A REVISION OF THE ASTACID.E. 



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

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

 anterior border bituberculate, posterior border unituberculate, transverse 

 fossa deep, recurved at each end. 



Measurements of male, form I. — Length of body, 40 mm. Length of 

 carapace, 25 mm. Length of rostrum, 6 mm. Length from 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 mm. 

 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 Zoology, from Irondale, Mo. 



This species has the general form of body, rostrum, and chela? of the 

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

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

 of the rami, on the anterior edge, as in C. rusticus, C. Pv&nami, etc. 0. im- 

 munii and C. Mississipjriensis, 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. figs. 8, 8 , 8 a, 8 a (first abdominal appendages of male). 



Cambarus rusticus, Girai;i>. 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, 



L870 

 Cambarus placidus, Hagi \. op. fit., p. 65, PI. I. figs. 70-7 c .», PL III. fig. 158, 1S70. 

 1 1 u,i;n. op. cit. p. 66, PI. I. Qg ■ I > 3 I, PI 111. fig. 157, 1S70. 



- mi Etep. 1 S. Comm. Fish and Fisheries for 1872 and 1873, p. 639, 1874. (After 

 i I gen. No description.) 

 Cambarus placidus, Smith, op cit. p. 638, 1874 (Alter Hagen No description.) 

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

 Cambarut Bundy, Bull [II. Mus. Nat Hist., No. I. p. 4, 1876. —Trans Wis Lead. Sci., V. 



181, 1882 i. ol w i- Surv. 1873-1879, I K)2, 1883 



. Forbes, Bull. 111. Mus. Nat. Hist., No. I. pp. I. 19, 1876. After Hagen.) 

 Cambat >■• Forb - op. cit., p. 19. (After Bundy.) 



Cambarus rustit r, Bundy, Trans. Wis. Acad. Sci., \ L81 L882. — Geol. Wis., Sun 1873-1879,1.402, 



1883. (Nol described.) 

 Cambarus placidus, Bundy, Traus. Wis Lead Sci \ 181,1882 (Not described.) 

 Camion i ixon, Proc Araer Lead Lrts and Sci., W L48, 1884. 



Male, form I. — Rostrum long, narrow, concave on the sides, excavated, 

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



