700 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxi. 



the abdomen. The dorsal surface of the segment has a few scattered 

 spines on either side at some distance from the mid-line. There is 

 also a row of .5-8 along the center of the lateral margin. 



Back of these and at about the centre of the lateral lobes is fastened 

 a triangular flap or membrane, nearly as long as the lobe, quite nar- 

 row, and extending diagonalh' backward and outward. 



It is ornamented around its edges with a row of short and stout 

 spines. 



The abdomen is cylindrical and two-jointed, the basal joint some- 

 what wider than the terminal and about half as long. 



Near the centre of the terminal joint on the dorsal surface is a large 

 knob, which is ornamented at the sides and abov^e by rows of short 

 spines. The posterior margin of this knob looks like the second joint 

 in the abdomen, but an examination of the ventral surface shows that 

 there is hut a single joint. 



The anal papillw are thread-like and about the same length as the 

 terminal joint. They are somewhat broken in all the specimens at 

 command, ])ut did not show any signs of the spines toward their tips, 

 as noticed by Thomson in Gloiopotes huttoni. The first antenna? are 

 large, the terminal joint longer than the basal, very narrow, cylindri- 

 cal, and wholh' destitute of setie. The second antennte are large and 

 stout, the basal joint considerabl}'^ flattened and reenforced posteriorly 

 b}' a short and broad spine, the terminal joint a strong claw with an 

 accessor}' seta upon its ventral surface. . 



The first maxilh>3 are small and three-parted, the two inner prongs 

 shorter and more acute than the outer, which is Inroad and spathulate. 

 The second maxiUaj are short, stout, and bifurcate for more than half 

 their length, the outer branch larger and longer than the inner. 

 These maxilla? are very chitinous and turn dark brown in alcohol, like 

 the tips of the claws and the spines. 



The maxillipeds are like those of Caligus^ the first pair long and 

 slender, the second ver^^ large and stout; the basal joint is swollen and 

 nearly twice as long as the slender terminal claw, which latter carries 

 a stout accessory seta on its inner margin. 



The furca is compound witii bifid branches, between which lies a 

 broad U-shaped sinus; the outer branch extends outward nearly at 

 right angles from the base of the central sinus; the inner branches 

 diverge somewhat; each is enlarged at the tip and subdivided there 

 into two short and blunt knobs. The central foramen has the form of 

 an isosceles triangle, the apex pointing backward. 



The swimming legs are very similar to those of Callgus; the two 

 inner terminal claws of the first pair are replaced by three-pronged 

 claws, the two ventral prongs being stout, situated side by side, and 

 strongly chitinous, while the dorsal one is slender and remains snowy 

 white even in alcohol (Plate XVII, fig. 31). 



