22 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 123 



25, 63, 64, 66, 74, 76, 95, 97; Xd. formosus at 10, 21, 89-92; and 

 Xg. instabilius at 3-5, 7, 9, 12, 21, 22, 24, 37, 44, 46, 53, 54, 60, 64, 

 56, 97, 121, and 123. 



Remarks. — As indicated above, C. b. bartonii is the most widely 

 distributed crayfish in the area, abounding in mountain brooks at 

 high elevations; in the smaller feeder streams at lower elevations 

 it is the sole crayfish inhabitant. As the cascading waters give way 

 to alternating riffles and pools or as the small feeder tributaries join 

 or become larger streams, other crayfishes encounter the C. b. bartonii 

 populations, and adult of this species, for the most part, occur only 

 along the littoral areas of the stream, where they may be found under 

 stones or burrowing into the banks. The absence of C. b. bartonii 

 from the collections in larger streams at lower elevations probably 

 does not indicate its absence from the streams, but only the fact 

 that it is rarer, and its habits at these elevations make specimens 

 much more difficult to obtain. 



Especially around springs, where the winter temperatures of the 

 water are not so low as in streams, this species is. active throughout 

 the year, and even in the streams it is more easily routed from its 

 lair than is C. I. longulus. Where the streams cut steep banks through 

 clay deposits, frequently C. b. bartonii and C. acuminatus dig tunnels 

 to the extent that the bank below the high water level is riddled with 

 their passageways, thereby hastening the erosion of the bank. During 

 the summer months, when some of the headwater streams are reduced 

 to a series of pools, C. b. bartonii digs burrows in the stream bed much 

 like the winter retreats of C. I. longulus. 



First form males have been collected from April to October and in 

 December. Females with eggs were found in June, July, and August, 

 and with young in August. 



Cambarus carolinus (Erichson) 



Figure 3 

 Astacus (Cambarus) carolinus Erichson, 1846, p. 96. 

 Cambarus carolinus Girard, 1852, p. 88 



Diagnosis. — Margins of rostrum slightly convergent to base of 

 acumen, where suddenly contracted to form obtuse angles at base of 

 acumen, neither thickened nor with marginal spines; areola always 

 at least eight times longer than broad with scattered punctations; sub- 

 orbital angle weak and obtuse. Chela with subovate fingers bearing 

 distinct median longitudinal ridges on upper surfaces; fingers only 

 slightly gaping and never provided basally with conspicuous tuft of 

 setae; inner margin of palm with two rows of tubercles. 



Range. — Not at all understood but reported from Greenville 

 County, S.C., northward in the mountains to Virginia, Pennsylvania, 



