80 astacim:. 



Cat. No. 240, Hickman's Landing, Kentucky River, Mr. A. Hyatt. 

 Fern. Spec. 1. 



Cat. No. 183, Osage River, Mr. Stolley. Male Form II. Fern. 

 Spec. 8. 



Cat. No. 237, Georgetown, D. C, Lanman. Male Form II., the 

 first pair of abdominal legs not articulated. Spec. 1. 



? Cat. No. 1101, Pico, Azores, Mrs. Dabney. Male. Fern. Spec. 4. 

 (The last locality is apparently erroneous.) 



Dry spec, Niagara, L. Agassiz. Male. Spec. 1. 



25. Cambarus robitstus Girard. 



Cambarus rdbustus Girard, Proc. Acad. Philad., T. 6, p. 90. 

 Antennal lamina, fig. 156, a ; epistoma, b ; spine of the second joint of the exterior antenna, c. 



C. Bartonii similis, sed differt : rostro excavato, longiori, antice angus- 

 tiori, acumine triangulari, rostri latitudine longiori; lamina antennarum 

 longiori, antice latiori; articulo antennarum secundo dente externo 

 acuto ; epistomate triangulari, lateribus paulo rotundatis ; thorace sub- 

 ovato ; linea thoracica spina utrinque laterali ; chela margine interim 

 serie duplice tuberculorum serrata, digito externo supra ac subtus im- 

 presso, excavato ; carpo tuberculo parvo inter spina antica et ilia ante- 

 riori marginis interni. 



Long. 3.2; antenn. 2.5; ped. ant. 2. 



Habitat: Toronto, Humber River; Genesee River, Rochester, and 

 Lake Regis, N. Y. Two females from Fredericksburg, Virginia (Salem 

 Mus.). 



I have seen one typical male, second, form, from Toronto, in the 

 Philadelphia Academy, and some specimens from New York, both forms 

 of the male and female, all full grown. The abdominal legs of the 

 male have somewhat more resemblance to those of C. latimanus. The 

 rostrum and the hands, the external finger of which shows a very visi- 

 ble impression, separate this species from C. Bartonii. 



C. obesas differs constantly in the linear areola. C. latimanus has no 

 lateral thoracic spine, a more rounded thorax, the carpus beneath 

 strongly tuberculated on the inner side ; besides the different and more 

 elongated rostrum, and the rounded not impressed under side of the 

 external finger. 



Cat. No. 176, Genesee River, Rochester, N. Y., Mr. H. A. Ward. 

 Male Form. II. Fern. Spec. 12.* 



Cat. No. 1176, Western New York, L. Agassiz. Male. Spec. 4. 



