372 Crangonyx 



with 6 setae, outer with 7 spiues, 2*^ Joint of palp with a few spinules on 

 apex. Maxiila 2, inner plate with 4 setae on inner margin, both plates 

 armed apieally. Maxillipeds, inner plates with 4 spine-teeth on trancate apex, 

 outer plates scarcely so large, not reaching apex of palp's 1^* Joint, fringed on 

 apex and inner margin with slender spines, palp elongate. Gnathopods 1- 

 and 2 similar, 5*^ Joint triangulär, cup-shaped, ö*'^ much longer, large, broadest 

 at base, the long, oblique, rather convex palra fringed with numerous spines, 

 the series continued beyond a large palra-defining spine, which the large 

 curved finger reaches. Peraeopods 1—3 slight. Peraeopods 4 and 5 rather 

 sti-onger and much longer. Peraeopods 3 — 5, 2*^ Joint long oval. Uropods 1 

 and 2 extendiug much beyond uropod 3, strongly spinöse. Uropod 1, peduncle 

 longer than subequal rami. Uropod 2, peduncle subequal to slightly unequal 

 rami. Uropod 3 short, peduncle rather broader than long, smooth, ramus much 

 naiTower and shorter, apieally spinöse. Telson about thrice as long as broad, 

 slightly tapering to the truncate, very spinöse apex. L. 12 — 14 mm. 



Texas (artesian well at San 3Iareos). 



3. C. vitreus (Cope) 1872 Stygohromus v., E. D. Cope in : Amer. Natural., v. 6 

 p.422 I \%^9) Crangonyx V., (S. I.Smith in:) Paekard in: Mem. Ac. Washington, vAi p. 34 

 t. 5 f. 1--4. 



Side-plate 4 the deepest, excavate behind, broader than any but the 

 5**^. Pleon Segments 1 — 3, postero-lateral corners obtusely quadrate. Eyes 

 wanting. Antenna 1 about ^g length of body, 1*** Joint as long as 2*^ and 

 3^ combined, flagellum rather longer than peduncle, 10-jointed. Antenna 2 

 shorter, flagellum about 6-jointed. Gnathopod 1, 5*^ Joint rather short and 

 broad, 6*^ wider and much longer, palm maldng a very obtuse angle with 

 the shorter bind margin. Gnathopod 2 much larger, 5^^ Joint short, triangulär, 

 cup-shaped, 6**^ large, widest at commencement of the long palm, thence 

 narrowing to hinge of finger, palm fringed with spines and defined from 

 the much shorter bind margin by 2 spines much longer than the rest, finger 

 strong, curved. Peraeopods 1 — 3 subequal. Peraeopods 4 and 5 subequal, 

 much longer than peraeopods 1 — 3; 2* Joint in peraeopods 3 — 5 oblong oval. 

 Uropods 1 and 2 extending beyond uropod 3 ; in uropod 1 peduncle considerably 

 longer than the subequal rami, in uropod 2 only a little longer than the 

 rami, of which the outer is a little shorter than the inner. Uropod 3, 

 peduncle short, stout, little longer than broad, Single ramus minute, scarcely 

 longer than broad, with 3 spinules at apex. Telson rectangular, nearly as 

 broad as long, apical margin with a very shallow sinus in middle, each side 

 of which is armed with several slender spines. Colour translucent, L. 9 

 over 5 mm. 



Kentucky (Mammoth Cave). Purrowing in the mud of pools. 



4. C. tenuis S. I. Sm. 1874 C. t., S. I. Smith in: Eep. ü. S. Fish Comm., v. 2 

 p. 656 j 1893 C. t., A. Della Valle in : F. Fl. Neapel, v. 20 p. 682. 



Slender, elongated. Side-plates very shallow, more as in Niphargus 

 than in Crangonyx. Eyes not perceived. Antenna 1 usually longer than 

 antenna 2, flagellum with 16 — 19 joints in antenna 1, with 8 — 10 in antenna 2, 

 but exceptionally large ö had 1^* antenna 5 mm long; flagellum twice as long 

 as peduncle, with about 22 joints, antenna 2 stout, 6 mm long, flagellum 

 as long as peduncle, 15-jointed. Gnathopods 1 and 2 differing little in the 2 

 sexes, gnathopod 1 the stouter, with palm more oblique, palm in both pairs 

 armed on each side with a series of stout, obtuse spines, with a notch and 



