426 EEPORT OP COMMISSIONER OF FISH AND FISHERIES. 



podus bears also a few setae, especially near the base of the outer tooth. 

 The forceps thus formed are in most cases large enough to close around 

 the body of another individual, but vary in size, being in some speci- 

 mens at least one-third smaller than in others. The basal antennular 

 segment may also be somewhat shorter than above described. 



Of the thoracic segments the second (first free) segment is the short- 

 est, and is also slightly broader than the others, and broader than the 

 head. The third, fourth, and fifth segments increase in length progres- 

 sively ; the sixth is as long as the fifth ; the seventh shorter. In the 

 second pair of legs, the dactylus with its terminal claw is about as long 

 as the propodus and nearly straight, as it is also in the third and fourth 

 pairs, but the dactyli of the last three pairs of legs are more curved, 

 and the basal segments somewhat swollen. 



The first five segments of the pleon are of about equal length. The 

 sixth is slightly shorter, obtusely pointed in the middle, and emarginate 

 above the bases of the uropods, which are composed of a robust basal 

 segment, bearing a minute outer ramus composed of a single segment 

 tipped with setae, and a five-jointed inner ramus, also sparingly pro- 

 vided with setae. Between the uropods and below, a thin spatulate plate 

 projects beyond the extremity of the pleou. 



In length the males vary from 2.G mm to 3.8 mm , and in breadth from 

 0.6 mm to O.S5 mra . The females measure in length about 2.3 mm ; in 

 breadth, 0.5 mm . 



About one hundred specimens of this species, three-fourths of them 

 females, were collected by Prof. A. Hyatt and Messrs. Van Vleck and 

 Gardiner, in three feet of water, on muddy bottom, in the summer of 

 1878, at Annisquam!, Mass., and are the only specimens I have seen. 



Leptochelia filum Harger (Stimpson). 



Tanais filum, Stimpson, Mar. Inv. G. Manaii, p. 43, 1853. 



Packard, Mem. Bost. Soo.. Nat. Hist., vol. i, p. '296, 1867. 



Harger, Am. Jour. Sci., III, vol. xv, p. 378, 1878. 

 LeptocJivlia filum Harger, Proc. U. S. Nat. Mus., 1879, vol. ii, p. 164, 1879. 



" Very minute, slender, rounded on the back, white, looking very much 

 like a short piece of thread. Head small, and rather narrowed in front; 

 first thoracic segment of great length ; the second half as long as the 

 third, which is about equal in length with the fourth, fifth, and sixth ; 

 the seventh being a little shorter than the sixth. The segments of the 

 abdomen are well defined, the first five equaling each other in length, 

 and the terminal one longer than the fifth, but narrower, and rounded 

 behind. Antennae short and thick, without flagellae, with blunt tips 

 crowned with few hairs, as are also their articulations. The inner ones are 

 directed forward, and much the stoutest, especially toward their bases; 

 while the outer ones are more slender and curve outward and backward. 

 First pair of legs exceedingly thickened, with very large ovate hands 

 and strong curved fingers. They are generally closely applied against 



