CAMBAEUS 



101 



thoracic spine is better developed, the antennse are longer (equal to the 

 length of the body), and the tufts of cilia on the inner side of the second 

 pair of legs are not developed. The anterior process of the epistoma is not 

 notched or truncated. The male appendages and the annulus ventralis are 

 as in the typical C.immunis. In the only old specimen (female, 4} inches 

 long) the rostrum and epistoma are, unfortunately, mutilated, but the chelae 

 are°broad 3 as in the typical form, and the second pair of legs show the ciliate 

 tufts. 1 am disposed to consider the variations here as varietal rather than 

 specific. The form may be called Cambarus immurris, var. spinirostris. 



The only specimens I have seen from the State of New York are a 

 pair, so labelled, in the collection of Prof. L. A. Lee. Two specimens in 

 the U. S. National Museum, male, form II., and female, from Orizaba, Mexico, 

 (Prof. Sumichrast.) do not differ to any extent from those inhabiting the 

 United States. 



42. Cambarus Mississippiensis. 



Plate III. «e. 8. Plate X. flgs. 4. 4 , 4 a. 4 a . 



Cambarus Mississippiensis, Faxon, Proc. Amer. Acad. Arts and Sci , XX. 123, 1884. 

 Male, form I. — Eostrum broad, twice as long as broad, subexcavated 

 above, smooth, foveolate at base, margins raised, converging anteriorly, sinu- 

 ate at apex ; acumen short, triangular, acute, no lateral teeth. Post-orbital 

 ridges sulcate on outer side, with short, blunt anterior spines. Carapace 

 densely punctate, sides lightly granulate, front lateral border not angulatcd. 

 Cervical groove sinuate, with small lateral and branchiostegian spines. Areola 

 linear anteriorly to the middle, with a small anterior and a larger posterior 

 triangular field. Length of areola equal to half the distance from tip of 

 rostrum to cervical groove. Abdomen as long as the carapace. Terminal 

 segment of the telson shorter than the basal segment, hind border slightly 

 concave al the centre ; basal segment bispinose on each side. Anterior angle 

 of epistoma notched. Sternum between the legs densely ciliated. Antennal 

 scale very broad, apical spine short. Third maxillipeds hairy without and 

 beneath. Chehv large, punctate, smooth below, margined without ; inner 

 margin of hand short, furnished with dentiform tubercles irregularly disposed 

 in a double series ; a little distance from these is another line of smaller cili- 

 ated tubercles on the upper surface of the hand on a line with the middle 

 of the base of the movable finger. Fingers Ion.-, gaping at base, each with 



