428 BULLETIlSr 15 8, UNITED STATES NATION" AL. MUSEUM 



nally outward and backward, their tips concealed beneath the posterior 

 lobes of the carapace. These lateral lobes are squarely truncated, 

 and each carries a small spine at its anterior corner. Lateral lobes 

 of the third and fourth segments evenly rounded, the fourth ones 

 short and giving the dorsal surface of the segment a lunate shape, 

 slightly overlapping the anterior margin of the genital segment. 

 The latter is barrel-shaped, with somewhat convex sides and minute 

 knobs at the posterior corners, with leg rudiments just in front of 

 the knobs. Abdomen less than half the width of the genital segment, 

 made up of two segments separated by a deep groove, the basal seg- 

 ment shorter and narrower than the distal. Caudal rami broad and 

 laminate, each tipped with four stout plumose setae. 



Antennae and mouth parts like those of the female, the second 

 antenna larger and armed with a long spine on the ventral surface 

 of the terminal segment. Basal segment of maxillipeds with two 

 large corrugated knobs and a larger hollow knob or cup, into which 

 the tip of the end claw shuts. Swimming legs as in the female, 

 except the fourth pair, whose exopods are 3-segmented while the 

 endopods are 2-segmented. Total length, 6.25 mm. Carapace, 3.6 

 mm. long and 4 mm. wide. 



Remarks. — This is the first description of the male of the species, 

 and it is found to be similar to those described for other species by 

 Heller, Thomson, and Olsson. But none of these authors noted any 

 accessory lobes on the posterior margin of the carapace, and the 

 present male shows a much greater relative width of the third and 

 fourth segments. The two males were found in company with fe- 

 males on the gills of an exceptionally large brown shark, Carcha- 

 rMnus onilherti^ captured in the pound nets at Menemsha Bight, 

 Marthas Vineyard, July 15, 1923. These males differ from those of 

 other species of the genus heretofore described in having the exopod 

 of the fourth legs 3-segmented instead of 2-segmented. 



ECHTHROGALEUS DENTICULATUS Smith 



FiGTJBB 268 



Echthrogalcus dentic-ulatus Smith, Report upon the invertebrate animals of 

 Vineyard Sound and adjacent waters, p. 282, 1874. — ^Wilson, Proc. U. S. 

 Nat. Mus., vol. 33, p. 369, pi. 20, 1907. 



Occurrence. — A single specimen was taken from Atwood's shark, 

 or the great white shark {Carcharodon carchaHas) ., in Vineyard 

 Sound by Prof. S. I. Smith. 



Distribution. — Not found outside the present area. 



Color. — The body of the preserved specimen is a uniform yellow- 

 ish brown. 



