no. 3602 CRAYFISHES — HOBBS, HOLT, AND WALTON 17 



2(1') Fingers of chela with weak longitudinal ridges above, broadly gaping and 

 with a conspicuous tuft of setae in gap; rostrum with much thickened, 

 convergent margins; areola with crowded, deep punctations. 



C. 1. longulus 



2' Fingers of chela with well-defined longitudinal ridges above and fingers 

 seldom broadly gaping; if so, then no conspicuous tuft of setae between 

 them; rostral margins may or may not be thickened but, if so, never 

 strongly convergent; areola usually with scattered punctations, if 

 crowded, never deep 3 



3(2') Lateral surfaces of carapace with a strong spine on each side immediately 

 posterior to cervical groove; rostrum with margins gently converging 

 mesially along almost entire length; postorbital ridges with spines. 



C. acuminatus 



3' Lateral surfaces of carapace with or without a well-developed tubercle 

 on each side immediately posterior to cervical groove but never with a 

 strong spine; margins of rostrum always suddenly contracted at base of 

 short acumen; postorbital ridges never with spines at anterior extremities. 



4 



4(3') Rostrum with thickened subparallel margins suddenly contracting to form 

 right angles (in mature specimens) at base of acumen . . C. sciotensis 



4' Rostrum with slender or moderately thickened margins that never form 

 right angles at base of acumen, angles obtuse or contractions rounded . 5 



5(4') Areola at least eight times longer than broad; inner margin of palm of 

 chela with cristiform row of tubercles flanked above by at least one or 

 two additional tubercles; color red; and seldom found outside of complex 

 burrows except in evenings after heavy rains when they wander over 

 land C. carolinus 



5' Areola never so much as eight times longer than broad; inner margin of 

 palm of chela with single row of appressed tubercles with occasional 

 two or three scattered tubercles flanking it above; color shades of tan, 

 green, or blue but never red; usually found in flowing water under stones 

 or debris or in burrows along banks of streams or ponds. C. b. bartonii 



Genus Cambarus Erichson, 1846 



Diagnosis.— Hobbs (1965, p. 267) stated: 



First pleopod of first form male symmetrical and terminating in two or three 

 distinct parts, usually only two (mesial process and central projection) bent 

 caudally or caudolaterally with principal axes of shaft and each ramus forming 

 angles of approximately 90 degrees; if mesial process and central projection 

 directed at angles of less than 90 degrees to main shaft, central projection never 

 comprising more than % of total length of appendage or bent at angle of less than 

 45 degrees; central projection corneous and flattened laterally; mesial process 

 mostly non-corneous, frequently inflated; caudal process, when present, forming 

 knob-like prominence at caudolateral base of central projection. Hooks present 

 on ischiopodites of third pereiopods only except in Cambarus dissitus Penn (1955, 

 p. 73) in which also present on those of fourth pereiopods. Opposable margins 

 of ischiopodites of third maxillipeds with teeth. 



244-775—67- 



