478 MEMOIRS OF THE CARNEGIE MUSEUM 



oble, Bucks County, Pennsylvania, September 20, 1904.) Males of the second form 

 are scarce, and most of them are of small size (between 28.5 and 40 mm. long). 

 Among the females also are many small individuals (as small as 25 mm. long). 

 These small specimens clearly belong to the youngest generation, born in the spring 

 of the year of capture. 



Copulation was observed by Mr. H. Gera on September 4, 1905. I saw a 

 repeated copulation of the identical couple on September 10, 1905, and again, in 

 other specimens sent to me alive by Mr. Gera, on November 4, 1905. In addition 

 I have seen this species copulating in captivity in the Anatomical Laboratory 

 of Princeton University in January, 1899, (Ortmann, 1900, p. 1242). Thus the 

 copulating season is identical with that of C. ohscarus, and lasts from September 

 into the winter, possibly January. 



C. limosiis goes through the winter,"^ and is found in spring in the same condi- 

 tion as in fall (April, 1899, at Princeton). In May I found females with eggs (May 

 9, 1905, Potomac River, (Jumberland, Maryland), and on May 30, 1898, I collected 

 females with young under the abdomen (Stony Bro(jk, Princeton, New Jersey). 

 Thus the spawning season seems to be identical witb that of C. ohscurus. During a 

 part of the summer males of the first form seem to be absent. I record that in July, 

 1904 (specimens collected by H. Gera in ( "amden County, New Jersey, without 

 exact date), no males of the first form were found. In a large set preserved in the 

 Academy of Natural Sciences of Philadelphia, collected by H. W. Fowler in tbe 

 Delaware River at Holmesburg, Philadelphia County, on July 4, 1899, all the males 

 are of the second form, and this although there are specimens in this set over 

 80 mm. long. Among the collections of W. R. McConnell there is a set of this 

 species taken on July 10, 1905, at Milesburg, Center ( "ounty, which contains two males 

 of the first form, with quite fresh shells. This date corresponds closely to the first 

 date (July 11), at which males of the first form of G. ohsctirus were observed.'' 



According to the above records it seems very likely that the seasonal history 

 agrees in every particular with that of C. obscums. The mating season in fall, the 

 spawning season in spring, and the absence of males of the first form in early 

 summer (June and part of July) agrees with what we know of G. obscurus. Com- 

 paring this with the account given by Andrews, we find the following differences. 



"I collected specimens in January, 1899, in the Delaware- Raritan Canal, near Princeton, New Jersey. All 

 the males were of the first form Collecting was done by seining under the ice. The crawfishes were obtained in 

 water about four or five feet deep. 



"Mr. McConnell collected a newly moulted male with a soft shell, of the first form, at Bloomsburg, Columbia 

 County, on July 19, !905, and during August he has several dates for these males : August 10 (Reading) ; August 18 

 (Marion) ; August 21 (Greenpark) ; August 22 (Landisburg). 



