558 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



the second pair very narrow and elongated, subcylindrical, slightly 

 flattened on the inner side, the jialmary margin longitudinal, and scarcely 

 distinct from the posterior margin.* Fourth segment of the abdomen 

 with a median fascicle of two large and two small spines, but no lateral 

 fascicles. Fifth and sixth segments with both median and lateral 

 fascicles of spines. 



Color in life grayish white, the posterior margins of the segments 

 bordered with brown, giving the body an anuulated appearance. 



Length, 12-18'"™. 



New Haven. Connecticut, and Eastport, Maine, and doubtless abundant 

 at other x)oints on the coast. 



This species closely resembles the fresh-water G. fasciatns, but is 

 distinguished from it by the proportions of the segments of the pedun- 

 cles of the antenn.T, and by wanting the lateral fascicles of spines upon 

 the fourth segment of the abdomen. 



Gammarus natator Smith, sp. nov. (p. 139.) 



Male : Eyes large, enlongated, but only slightly reuiform. Anteu- 

 nula short and stout, about three-sevenths as long as tliabody ; flagellum 

 but little longer than the peduncle ; secondary flagellum nearly half as 

 long as the primary. Antenna considerably longer than the antennula; 

 penultimate segment of the peduncle reaching to the extremity of the 

 peduncle of the antennula ; ultimate segment of the peduncle longer 

 than the penultimate; flagellum about two-thirds as long as the pedun- 

 cle. Both antennulie and antenniv are furnished with very long hairs, 

 of which many on the antennuhe are plumose. First, second, and third 

 epimera margined on the inferior edges with long cilia. First pair of 

 legs more slender than the second; propodus oval, twice as long as 

 broad, palmary margin continuous with the inferior, with a very narrow 

 lamellar edge, a stout obtuse spine in the middle, and two smaller ones 

 at the inferior angle ; dactylus strongly curved. In the second pair the 

 I)ropodus is more than half as broad as long, and somewhat rectangular 

 in outline, except that the palmary margin is slightly oblique; the pal- 

 mary margin has a narrow lamellar edge, with a slight emarginatiou in 

 the middle, from which a stout obtuse spine arises, and at the inferior 

 angle there are two or three smaller spines, as in the first pair. The 

 inferior edges of the car])i and propodi of both pairs of legs are thickly 

 clothed with long hairs. Natatory [legs reaching to the tips of the 

 telson. Second and third segments of the abdomen with the sides 

 produced backward, and the postero-iuferior angle acute. Fourth 

 segment with only a median fascicle of spines ; fifth and sixth 

 segments with median and lateral fascicles. Kami of the posterior 

 caudal stylets lanceolate, five or six times as long as broad,, the outer 

 extending beyond the inner by the length of its terminal article, which 

 is very slender, almost spiniform, the edges of both rami clothed with 

 long plumose hairs. Each division of the telson nearly three times as 

 long as broad. 



