32 PROCEEDINGS OF THE 5fATI0N"AL MUSEUM vou 82 



being flattened and has a spine on the outer margin and two smaller 

 ones on the end. 



Length, 1.52 mm. 



OccuiTence. — Found in Dutch East Indies at Kangeang and Aru 

 Islands in salt water. 



PSEUDODIAPTOMUS CORONATUS Williams 



Plate 16, Figures 3-6 



Pseudodiaptomus coronatus Williams, 1906, pp. 641-644, figs. 1-7. — Wilson, 

 1932, pp. 101-103, lig. 68. 



Female. — The last thoracic segment is rounded. The abdomen 

 (pi. 16, fig. 3) consists of four segments, the second and third ordi- 

 narily imperfectly separated. The first abominal segment has rows 

 of small spines on the dorsal surface at about one-half its length and 

 spines on the distal margin; it is enlarged in front and has a pair 

 of linguiform flaps over the genital aperture. The length of the 

 f ureal rami is about eight times their width; they are ciliate on 

 both inner and outer margins. There are two egg sacs, but the right 

 is aborted, containing commonly only two ova; sometimes the right 

 is entirely lacking. The first antennae are composed of 22 seg- 

 ments and about equal in length the cephalothorax. The exopod of 

 the second antennae is apparently 6-segmented. (PI. 16, fig. 4.) 

 In the fifth foot (pi. 16, fig. 5) the distal margins of the second 

 segment of the basipod and the first segment of the exopod are 

 armed with small spines. There is a spine at the exterior distal 

 angle of the first segment of the exopod. The second segment of 

 the exopod terminates in a rather long curved hook ; there is a spine 

 at the outer distal angle and, near the inner angle, a broad plumose 

 spine. A small spine is attached to the base of the hook. The first 

 segment of the exopod is more than twice as long as the second. 



Length, 1.5 mm. 



Male. — There is an endopod (pi. 16, fig. 6) on the left fifth foot. 

 The first segment of the basipod of the right foot is extended on the 

 inner distal angle into a stout spine reaching about one-half the 

 length of the second segment of the basipod; its inner border has a 

 short spine. The first segment of the right exopod has a stout blunt 

 spine projecting from its dorsal surface; this spine is three-fourths 

 as long as the segment. The inner border of the segment has short 

 spines like those on the second segment of the basipod and near 

 the proximal end a flask-shaped spine; this spine seems to be con- 

 stant in the species. Dahl figures a similar spine in P. richardi. 

 The second segment of the exopod has an acute external spine at 

 about three- fourths of its length. The terminal hook is nearly * 



