94 A REVISION OF THE ASTACIDJC. 



Neither of these forms has been reported from Pennsylvania or Vii-ginia. 

 Tiie only species known to mo to be common to the three States of New 

 York, Pennsylvania, and Virginia are G. Blandimjii, affinis, and Bartonii. Ra- 

 finesque's description fits none of them. Girard surmised, Irom the habits 

 of C.fosso)-, that it might prove to be C Dioyciics. 



In tlie collections of the Boston Society of Natural History and the 

 Museum of Comparative Zoology (Cat. No. 8590) there are three second- 

 form males of a Cambarus which closely resemble C jJ/'cpinquits, but the 

 sexual appendages are longer, as in C. rusticus. The epistoma is long. The 

 carpus has a strong internal median carpal spine and a small basal interntil 

 spine ; beneatli, the carpus is unarmed. The biserial spines of the meros 

 are well developed. The outer ramus of the first abdominal appendages is 

 a little recurved at the tip. The largest of these specimens is lb mm. long. 

 No locality is given. They seem to belong to an undescribed species. 



39. Cambarus Harrisonii. 



Plate III. flg. 1, Plate IX. figs. 9, 9'. 



Camhants Harrisonii, Faxon, Proc. Amcr. Acad. Arts and Sci., XX. 130, 1S81. 



Male, form I. — Rostrum long, narrow, deflexed, excavated ; margins 

 thickened, a little convergent ; acumen of moderate length, triangular, 

 acute ; marginal spines short, obtuse, often obsolescent. Carapace flattened 

 above, coarsely punctate, granulate on the sides; post-orbital ridges prom- 

 inent, sulcate without, with acute anterior spine; antero-lateral margin 

 notched at base of antenna ; cervical suture not sinuate, interrupted on the 

 side ; lateral spine small, acute ; branchiostegian spine obsolete ; areola at 

 least one half as long as the distance from the tip of the rostrum to the 

 cervical groove, of moderate width, punctate, the dots tending to a biserial 

 arrangement in the middle portion. Abdomen as long as the cephalothorax ; 

 telson long, posterior margin rounded, posterior margin of basal segment 

 bispinous on each side. Basal segment of antennule with an internal, sub- 

 apical, inferior spine. Antenna) as long as the body ; second segment armed 

 with a short, acute, external .spine ; scale as long as the rostrum, of moderate 

 width, widest near the middle, thence tapering to the acute external apical 

 spine. Anterior process of epistoma with convex sides, apex blunt or trun- 

 cate. Third pair of maxillipeds hairy within. Chelipeds of moderate length, 

 thick; chela large, broad, coarsely punctate above and below, inner margin 



