MEXICAN, CENTRAL AMERICAN, AND CUBAN CAMBARI 1 7 



liform. Those of the fourth pereiopod very strongly devel- 

 oped, swollen and inflated, tapering to a blunt point; coxofio- 

 ditc of third pereiopod with a semicircular, elevated, compressed 

 tubercle, that of the fourth pereiopod with a strong, triangular 

 spine, directed outward ; that of the fifth pereiopod with a small, 

 spiniform tubercle below genital opening, directed downward. 



Fig. 4. Cambarus -tuiegmanni Erichson. First pleopod (right side) of male 

 (I), a, outer view; b, inner view. Enlarged about three times. 



First -plcopods (Fig. 4) rather long and slender for the sub- 

 genus Cambarus, reaching to the coxopodites of the second perei- 

 opods, almost straight, very slightly curved ; truncated at the 

 tip, with three horny teeth, of which the outer one is compressed 

 and truncated, crescentic in shape ; the inner tooth is broadly 

 triangular, and the anterior is short and spiniform, 1 the inner 

 part of this organ terminating in an almost straight spine, which 

 is only slightly directed outward, and is slightly longer than the 

 truncated outer part, and has a distinct horn)' tip. 



Measurements : Total length 60 mm. ; carapace 29, anterior 

 part of carapace 18.5, posterior 10.5; width of areola 1.75; 

 abdomen 31 ; length of hand 25.5, width of palm 9.5 (Erichson 

 gives the following figures: total length 52 mm., length of 

 hand 17 mm., width of hand 6.5 mm. Hagen gives 66 mm. 

 as total length.) 



Comparing the present male with the description of the spe- 



1 This latter one seems to belong to the inner part; but I suspect strongly 

 that such is the case also in other species of the subgenus. The homologies of 

 the sexual organs of Cambarus are altogether not well understood, and urgently 

 need a more close study. 



Proc. Wash. Acad. Sci., May, 1906. 



