124 A EEVISIOX OF THE ASTAC1D.E. 



52. Carabarus Shufeldtii. 



Plate VII. flB. 1, Plate X. figs. 8, 8', 8a, 8a. 



Cambarus Shufeldtii, Faxon, Proc. Aiiier. Acail. Arts and Sci., XX. 134, 1S84. 



Male, form I. — Rostriun plane above, margins a little convergent, raised 

 into a slight rim from the base to the lateral spines, which are prominent 

 and acute ; acumen of moderate length, acute, pubescent. Post-orbital 

 ridges with anterioj: spines. Carapace smooth ; a sharp spine on the cervi- 

 cal groove on each side ; sub-orbital angle prominent, branchiostegian spine 

 present. Areola of moderate breadth. Telson bispinous on each side. 

 Epistoma triangular. Antennal scale broad. Hand smooth, cylindrical, in- 

 flated; fingers slender, incurved at the tips. Carpus smooth, armed with 

 a single spine on the antero-inferior border. Meros provided with a single 

 spine near the distal end of the superior margin, and two or three below. 

 Third segment of second and third pairs of legs hooked. First pair of ab- 

 dominal appendages straight, bifid, inner part ending in a straight, acute tip, 

 outer part split at the tip into two straight acute points. 



In the second form of the male the hooks upon the thoracic legs are very 

 slightly developed, and the first abdominal appendages are less deeply cleft, 

 with blunter and less finished tips. The chela is shorter. 



In the female the chela is much shorter, broader, and less cylindrical, the 

 abdomen broader. Annulus ventralis a transverse curved ridge, the hind 

 side of the ridge concave. 



Length, 19 to 27 mm. 



Locality. — Near New Orleans, La. 



Found with C Clarkii in the collection made by Dr. R. W. Shufeldt, 

 U. S. A., in 1883, now in the U. S. National Museum. 



This is a minute species closely related to C. Montczmmc from Mexico. 

 Like that sjiecies, it has the second and third pairs of legs hooked in the male, 

 a condition which normally obtains in no other species known.* C. Shufeldtii 

 is distinguished from C Montcsumcc by the presence of a lateral spine on the 

 carapace and by the form of the male appendages. In the latter species the 

 tips of these appendages are recurved, the inner part flattened at the end 

 into a spoon-shaped surface. In C. Shufeldtii the tips of these organs are 

 straight, and each of the three points in which they terminate is acute. 



* I have seen two or three abnormal speeimeus of C. virilis and C. propiiiqiius with a like dispositiou 

 of hooks on the legs. The same arrangement is fonnd in the three species of Canibaroidcs from the Amoor 

 River basin and Japan. 



