1852.] 87 



The Committee on the following paper by Mr. Charles Girard, of 

 Washington, reported in favor of publication in the Proceedings : 



A Revision of the North American Astaci, with observations on their habits and 



geographical distribution. 



By Charles Girard. 



According to recent investigations,* the crawfishes or Astaci, have been dis- 

 tributed into several genera : thus, the genus Astamis proper includes all the 

 species of Europe and Asia, and two of Australia ; the genus Astacoides is com- 

 posed of two species one from Madagascar and another from Van Diemen's 

 Land ; the genus Chr,raps comprehends three species peculiar to New Holland ; 

 the genus Engceus embraces two species confined to Van Diemen's Land ; and 

 finally, the genus Camharus includes the American species: one from Chili, 

 another from Cuba, two from Mexico and six from the United States. 



Investigations of a still more recent date,t the results of which have not yet 

 been given to the scientific world, refer to the genus Astacus a species from the 

 Columbia river, thus giving again that genus to North America. 



At the request of Dr.Baird, we have examined critically the Astaci preserved at 

 the Smithsonian Institution, collected chiefly by himself. Our researches have 

 made us acquainted with several new species within the limits of the United 

 States, and which we now characterise briefly, deferring to another opportunity 

 ipore full descriptions, accompanied with necessary graphic illustrations. 



First group. Rostrum subquadrangularly elongated, terminated anteriorly by 

 three conical and acute spines, the two lateral smaller than the middle one, 

 which forms the tip. Extremity of the anterior pair of abdominal legs (in the 

 male) straight and acute. 



1. Ca:vibarl's PELLrciDus, Erichs. Arch. f. Naturg. 1846, i. 95. 



Astacus pellucidus, Tellk. in Mull. Archiv, 1844, 383. 

 Locality. Mammoth Cave, Kentucky, (Tellkampf, &c.) 



2. Cambarus affinis, Erichs. Arch. f. Naturg. 1846, i. 96. 



Astacus affiiiis, Say, Journ.Acad. Nat. Sc. Philad. i. 1817, 168 and 443. 



Harl. Med. and Phys. Res. 1835, 230, fig. 2. 

 A. Barto7iii^ M. Edw. Hist. Nat. Crust, ii. 331. 

 A. limosns, Rafin. Amer. Month. Mag. ii. 1817, 42. 

 Localities. Schuylkill, at Reading (Baird), Delaware (Say and Rafinesque). 



3. Ca-mbari's oreganus, Erichs. Arch. f. Naturg. 1846, i. 375. 



Astacus uregajius, Rand. Journ. Acad. Nat. Sc. Philad. viii. 1, 1839, 

 138, PL vii. 

 Locality. Columbia River (Nuttall). 



4. Cambarus Pealei, Girard. Diff'ers from C. affinis in having longer anten- 

 nae, and a broader area between the dorsal lines of suture of the carapace. The 

 lateral spine of the rostrum are also much less developed. The color is green- 

 ish brown above, with small green dots on the claws, and sometimes on the 

 cephalo-thorax. A green line or narrow band is observed along the outer edge 

 of the big claws, the tips of which, as well as the tips of the other legs, are 

 orange, preceded by a deep green, almost black circle or ring. On each articu- 

 lation of the tail there is a double, irregular and transverse blood-red band, 

 which extends to the lateral appendages of the caudal rings. Underneath, the 

 body is whitish and rusty. 



Locality. Potomac, at Washington (D. C.) 



Erichson (W. F.) Uebersicht der Gattung Astacus. Wieg?n. Archiv fiir 

 Naturgeschichte, 1846, i. 86. 



t Proc. Acad. Nat Sc. Philad. vi. 1852, 20. 



14 



