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. obscwrus, and lasts from September 
into the winter, possibly January. 
C. limosus 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, Cumberland, Maryland), and on May 30, 1898, I collected 
females with young under the abdomen (Stony Brook, Princeton, New Jersey). 
Thus the spawning season seems to be identical with that of C. obscurus. 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 Camden 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 the 
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 County, 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 C. obscurws were observed.” 
According to the above records it seems very likely that the seasonal history 
agrees in every particular with that of C. obscwrus. 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 C. obscwrus. Com- 
paring this with the account given by Andrews, we find the following differences. 
14] 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. 
7>Mr. McConnell collected a newly moulted male with a soft shell, of the first form, at Bloomsburg, Columbia 
County, on July 19, 1905, and during August he has several dates for these males: August 10 (Reading) ; August 18 
(Marion) ; August 21 (Greenpark) ; August 22 (Landisburg). 
