ASTACIDiE. 9 



the tip of which is rounded. (9 spec.) III. Rostrum very much elon- 

 gated, conical, tapering, provided on both sides and rather near the ex- 

 tremity with a small and acute spine, sometimes, however, but very 

 slightly developed. (4 spec.) 



Concerning the species described by Mr. Ch. Girarcl, — I have given 

 my opinion at some length in my descriptions, — I may here make the 

 following remarks : C. Pealei I consider as a full-grown C. affinis ; C. 

 montanus, Diogenes, and pusilhis I am not able to separate from C. Bar- 

 tonii ; and C. hngnlus is possibly an abnormal specimen of the same 

 species. C. Blandingii is not the species described by Harlan, but is 0. 

 troglodytes, Le Conte. C. acutissimus is the second form of the male of 

 C. acutus. Some of my determinations may be incorrect ; I hope here- 

 after to be able to compare the typical specimens preserved in the col- 

 lection of the Smithsonian Institution. 



The description and the detailed account of the burrowing habits of 

 C. Diogenes given by Mr. Ch. Girard are very interesting, and, so far as 

 I know, they are still the most complete description of this peculiar 

 manner of living. Besides the remarks by Mr. John D. Godman, which 

 I have not seen, Professor Erichson has mentioned the burrowing habits 

 of some Australian species, and in the last edition of Cuvier's " Regne 

 Animal," the burrowing habits of an American species which severely 

 damages the rice-fields of the Southern States are quoted from a com- 

 munication by Dr. John Le Conte. 



1855. Dr. John Le Conte has given, in the Proc. Acad. Phila., VII. 

 400, "Descriptions of new Species of Astacus from Georgia." Of the 

 species described by Mr. Ch. Girarcl all but one are from the South, the 

 others are from the Northern, and mostly from the Eastern States. 

 Therefore Dr. John Le Conte's monograph is far more interesting. He 

 describes nine species from Georgia, eight new ; and there are two 

 more, only seen by him. He remarks that he has preferred the old 

 generic name Astacus, because the very slight and not very apparent 

 differences which has been adopted to distinguish these two genera ap- 

 pear to him of little moment. Their color, says Dr. John Le Conte, is 

 generally lost with their life, so that it is of little value in the descrip- 

 tion. "All that I have ever seen were much of the same color, — a red- 

 dish brown, inclining to dark olive." I do not find that any marks can 

 be definitely pointed out by which we can distinguish those which are 

 subterranean from those which are aquatic. It is possible to determine 

 the species by the elaborate descriptions, especially by the shape of 

 the rostrum and the hands, and the breadth of the areola. The types 

 of six species, contained in the Museum of the Philadelphia Academy, 

 have been kindly communicated to me by Professor Leidy, viz. A. 

 troglodytes, spiculifer, fossarum, angusicdus, ledimanus, advena. 



Concerning his species, I would remark that A. troglodytes is sy- 



2 



