COPEPODS OF THE WOODS HOLE EEGION 251 



outer margin. Rudiments of a sixth pair of legs are present on 

 the ventral surface of the genital segment in the form of a broad 

 lamella on either side, armed with three subequal setae. Total 

 length, 0,3-0.4: mm. 



Remarks. — This species may be recognized by its minute size, its 

 elongated cylindrical body, and its peculiar caudal rami. It is pe- 

 culiar in that the male shows no sexual modifications in the swim- 

 ming legs. Its joints are all mobile, and it moves about in the inter- 

 stices between the sand grains much like a worm, twisting and 

 crawling in every direction. The peculiar spines on the inner mar- 

 gin of the end segment of the fourth exopod in the female are also 

 noteworthy and are not found in the following species, 



PARALEPTASTACUS KATAMENSIS, new species 



Plate 10 



Occurrence. — Two females and three males w^ere washed from the 

 sand on the shore of Katama Bay, Marthas Vineyard, August, 1927. 

 The male holotype is U.S.N.M. No. 63429. 



Color. — Body transparent and whitish, without pigment mark- 

 ings ; eye invisible. 



Female. — Cephalothorax as long as the two following segments 

 combined, and the same length as the genital segment; rostrum 

 relatively shorter than in hrevicavda., but tiiangular and not well de- 

 fined at its base. Genital segment not divided, one-half longer than 

 the fifth segment ; anal segment as long as the penultimate segment ; 

 anal operculum with a smooth posterior margin. Caudal rami 

 longer than wide, each with a long stout spine at its inner distal 

 corner, a short spine inside of it and two slender setae outside of it, 

 and a slender seta on the dorsal surface of the ramus close to its tip. 



First antennae 7-segmented, the second segment elongated, with a 

 longitudinal row of three setae on the dorsal surface, the middle seta 

 of the three sometimes transposed to one side, out of line with the 

 other two. The aesthetask on the fourth segment reaches well be- 

 yond the tip of the antenna ; the apical segment is armed with eight 

 or ten setae, the others are sparsely setose. The basal segment of 

 the endopod of the second antenna is more distinctly divided than 

 in the preceding species, the exopod is much shorter and is attached 

 at the joint. In the second maxillae the two terminal claws are 

 longer and enlarged at the base, the outer spine is changed to a 

 fingerlike process with a tuft of cilia at its tip, and the two short 

 spines on the inner process are ciliated. The terminal claw of the 

 maxillipeds is one-half longer than the second segment, is pectinate 

 near the tip, and carries an outer accessory spine. 



