Ceangontx tenuis, sp. nov. 



A slender, elongated species, with very low epiinera, resembling more 

 n form the species of Niphagus than the typical species of Crangonyx. 



Eyes not observable in alcoholic specimens. Secondary flagellum 

 of the antenulae very small, composed of two segments, of which the 

 terminal is very short. 



First and second pairs of legs differing but little in the two sexes. 

 First pair stouter than the second, and with the palmary margin of the 

 propodns much more oblique; the palmary margin of the propodus of 

 both pairs, and in both sexes, armed each side with a series of stout, 

 obtuse spines, with a notch and a cilium near the tip. 



First three segments of the abdomen longer than the last three of the 

 thorax; fourth, fifth, and sixth together scarcely longer than the third. 

 Caudal stylets all extending to about the same point. First pair with 

 the rami subequal, scarcely half as long as the peduncle. Peduncle in 

 the second pair reaching a little beyond the peduncle of the first pair; the 

 rami very unequal, the outer only half as long as the inner. Posterior 

 pair scarcely as long as the telson; the single terminal segment very 

 small, and tipped with four or five setiform spinules. Telson two-thirds 

 as broad as long, tapering very slightly toward the entire and slightly 

 arcuate posterior margin, which is armed with about ten slender spin- 

 ules. 



In the largest male seen, 13 mm .5 in length, (excluding the antennae,) 

 the antennulae are about 5 mm long; the flagellum being twice as long as 

 the peduncle, and composed of about twenty- two segments, while the 

 antennae are stout, fully 6 mm long, and the flagellum as long as the 

 peduncle, and composed of fifteen segments. All the females and most 

 of the males which I have seen are much smaller, being 6 mm to 8 mm in 

 length, and in these the antennulae are longer than the antennae; and the 

 flagellum of the antennulae is composed of sixteen to nineteen segments, 

 while that of the antennae has only eight to ten. 



The only specimens which I have seen were found in wells at Middle - 

 town, Conn., and were sent to me by Mr. (x. Brown Goode. 



