88 [May, 



5. Cambarus RusTicus, Girard. Rostrum narrower than in both C affinis 

 and C. Pealei, and besides, concave on the sides. Terminal point shorter than 

 in either of the preceding species ; anterior pair of abdominal legs (in the male) 

 elongated, slender, with their tip curved inwards, whilst the same tips are 

 straight in C. affinis y and twisted in C. pelhicidus. The dorsal area is broader 

 than in C. Pealei. 



'' Locality. The Ohio, at Cincinnati, 



6. CAMBARrs pRopiNQUus, Girard. Closely allied to C. affinis, from which 

 it differs, as well as from C. Pealei, by a proportionally shorter rostrum, and 

 from C. rusticus by a much broader one. The area between the dorsal sutures 

 of the carapace is still broader than in either C. affinis, C. Pealei or C rusticus. 

 There are also differences in the structure of the anterior pair of abdominal legs 

 of the male. . " 



Localities. Lake Ontario, four miles from the shores, opposite to Oswego, 

 found in the stomach of Lota maculosa; Garrison Creek, Sackett's Harbor; 

 Four-mile creek, Oswego (Baird). 



7. Cambarus fossor, Girard. Astacus fossor, Rafin. Amer. Month. Mag. ii. 

 1817,42. 



This species we have not seen, but if Rafinesque's description is correct, 

 " rostrum short, one toothed on each side, "^there can be no hesitation in referring 

 it to this group. He further states that its vulgar name is " burrowing lobster," 

 and that " it burrows in meadows and mill-dams, which it perforates and da- 

 mages." This would indicate habits similar to a species of the second group, 

 which we*describe hereafter, under the name of C. diogenes. We cannot help, 

 however, from expressing some apprehension that on the examination of au- 

 thentic specimens from the same localities whence Rafinesque had obtained his, 

 the rostrum should be found without lateral tooth, in vv^hich case the C. fossor 

 might not differ from our C. diogenes. 



Localities. Virginia, Pennsylvania and New York (Rafinesque.) 



Second group. Rostrum generally broad, conical and short, with margins 

 entire and toothless, terminated anteriorly by an acute and comparatively short 

 point. Anterior pair of abdominal legs (in the male) recurved on their extremity, 

 the tip of which is rounded. 



8. Cambarus Bartonii,, Erich. Arch. f. Naturg. 1846, I, 97. 



Astacais Bartoiiii, Fabr. Ent. Syst. Suppl. 407. Latr. Gen. Cr. and Ins. v, 

 240. Bosc, Hist. Nat. Cr II, 62, pi. II, fig. 1. Say, Journ. Acad. Nat. Sc. 

 Philad. I, 1817, 167 and 443. Harl. Med and Phys. Res. 1835, 230, fisr. 3. 

 Gould, Rep. Inv. Mass. 1841, 330. De Kay, N. Y. Fauna VI, 1844, 22, pi. 

 viii. fig. 25. 



Astacus ciliaris, Rafin. Amer. Month. Mag. II, 1817, 42. 



Localities. Foxburg, Carlisle and Berwick (Pa.) ; New York (De Kay) ; Mas- 

 sachusetts (A. A. Gould). Brooks near Fishkill, Newburg, &c. (Rafinesque.) 



9. Cambarus carolinus, Erich. Arch. f. Naturg. 1846, I, 96. 

 Astacus affiuis, M. Edw. Hist. Nat. Cr. II, 332. 

 Localities, Carolina (Erichson); Anderson, S. C. 



10. Cambarus montanus, Girard. Antennae more elongated and more fili- 

 form than in C Bartonii. Rostrum intermediate in shape between the latter 

 and C. carolinns, being proportionally longer than in C.Bartouii and shorter and 

 less tapering than in C. carolinus. Dorsal sutures of the carapace more apart 

 than in both of the latter species. 



Localities. Within the Alleghany ranges in Virginia and Maryland: tributaries 

 of James river in llockbrid^^e Co. (Va.); Shenandoah river in Clarke Co. (Va.), 

 and Cumberland (Md.) of the hydrographical basin of the Potomac ; Sulphur 

 Spring, Greenbrier river, an affluent of Kenhawa river (Va.) of the Ohio basin. 



11. Cambarus diorenes, Girard. Rostrum proportionally the most elongated 

 and the most conical amongst all the species of (his group. Dorsal lines of 



