8 ASTACID^E. 



the five following : C pellacidus, Carolinns, pusilhis, Nebrascensis, acuttis, 

 nor the two species which he had not seen himself, C. Oreganus and 

 fossor. 



Mr. Ch. Girard has adopted the generic name Cambarus Erichson for 

 the American species described by him. The introduction to Mr. Ch. 

 Girard's Revision, etc., " according to recent investigations (Erichson is 

 here quoted alone), the crawfishes, or Astaci, have been distributed 

 into several genera," does not agree at all with Erichson's words. 

 Erichson, in his monograph, p. 86, in dividing the old genus Astacus, 

 expressly says : " The five groups quoted seem to have a higher value 

 than merely subdivisions. Perhaps hereafter they will constitute gen- 

 era. They may provisionally be regarded as subgenera." Mr. Girard 

 added that Mr. James D. Dana had reclaimed the genus Astacus for 

 North America by a species from the Columbia River, — A. leniusculus. 

 Subsequently, Proc. Acad. Phil., VI. 375, Professor Agassiz stated that 

 C. GambeUi, described as Cambarus by Mr. Ch. Girard, possesses six 

 pairs of gills like the crawfishes of Europe, and does not belong to 

 Cambarus at all. This statement is the more striking-, as Erichson only 

 gives as the character of Cambarus, " no gills on the fifth legs." The 

 reply of Mr. Ch. Girard, 1. c, p. 381, that he was not satisfied that this 

 peculiarity is of generic value, and consequently that he described C 

 Gambelii as Cambarus with the same propriety as he might have placed 

 it in the genus Astacus, gives no more light upon the characters of 

 generic value which induced Mr. Ch. Girard to separate Cambarus as a 

 distinct genus. In his Revision, etc., nothing more is said concerning 

 this point, and he has not given any other character for his genus Cam- 

 barus, including C GambeUi and Oreganus. 



It is to be regretted that Mr. Ch. Girard has not fulfilled his plan of 

 giving more full descriptions, accompanied with the necessary graphic 

 illustrations. His short descriptions are not sufficient to indicate his 

 new species with certainty, and for the species previously published the 

 synonymy alone is given, for which reasons it is impossible to prove 

 that his determinations are unquestionable. It is to be acknowledged 

 as a fact of value, that Mr. Ch. Girard first used in his descriptions the 

 specifically different shape of the first pair of abdominal legs in the 

 male, and the different breadth of the dorsal area. 



He has divided the species into three groups, with the following char- 

 acteristics : I. Rostrum subquadrangularly elongated, terminated ante- 

 riorly 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. (7 spec.) II. Ros- 

 trum generally broad, conical, and short, with margins entire and tooth- 

 less, terminated anteriorly by an acute and comparatively short point. 

 Anterior pair of abdominal legs in the male recurved at their extremity, 



