492 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



and very slender. Oculiferous tubercle very prominent, conical, very 

 acute. Eyes black, oval or nearly round. Abdomen small, tapering, 

 often bent upward. 



Eostrum large, somewhat variable, but usually shorter than the ocu- 

 liferous segment, slightly swollen at the extremity. 



AutenniB slender, basal joint about as long as the rostrum 5 chela 

 similar to that of X. longitarse^ but stouter, the claws shorter, slightly 

 hairy. 



Palpi slender, with a few small hairs most numerous on the outer 

 joints; basal joint nearly quadrate, about one-fourth the second; third 

 slightly longer than the first two united ; fourth less than half the third ; 

 fifth longer, slender, tapering, somewhat variable, being stouter in some 

 Bpecimens than in others. 



Accessory legs very slender. In the female they are, on an average^ 

 about one-eighth the extent of the legs ; in the male about one-sixth. 

 The joints have nearly the same proportions as in N. longitarse, but the 

 fourth and fifth joints are longer and still more slender. 



Legs long and slender, proportions of the first six joints nearly as in 

 2f. Stroma. Tarsus extremely variable in length (PI. YII, figs. 1 & to 1 ^) ; 

 in young specimens it is less than half the propodus, while in some large 

 adult specimens it is nearly twice that joint ; the propodus is armed, on 

 the inferior margin, with a series of slender, slightly curved spines, 

 which are longest proximally; dactylus about two-thirds the propodus; 

 auxiliary claws less than half the dactylus. The legs are sparsely hairy, 

 the hairs often forming, as in K. longitarse, a semickcle on the outer ex- 

 tremities of the joints. Color, when living, light salmon-yellow, the legs 

 often banded with reddish or light purple. Length 10.5 millimeters ; 

 extent 90 milhmeters. 



This species is, in most of its characters, extremely variable. Kroyer's 

 N. brevitarse and W. mixtum are undoubtedly, I think, forms of N. gros- 

 sipes. The former are young specimens, with a short, thick neck, very 

 short tarsus, and abbreviated rostrum; the latter are those having a long 

 slender neck, and with the tarsus from one and a half to two times the 

 propodus. From the large collection in the Peabody Museum I have 

 formed an almost complete series from extreme forms of N. brevitarse to 

 undoubted K. mixtum, though in none of the specimens of the latter 

 species is the tarsus quite so long as that figured in the Voy. en Scand., 

 Laponie, etc. The palpi, also, vary considerably with age. 



The variation is due in part to age, but is not sexual, since male 

 specimens with egg-masses present the same differences. In some speci- 

 mens the anteunoe are tipped with brown, or jet black; in others they 

 are white. The terminal joint of the legs is sometimes similarly tipped 

 with brown. 



The following table gives the relative length of the tarsus and propo- 

 dus in a series of specimens selected to show the variation. The joints 



