CUMACEA. 171 



Cyclaspis herdinani, n. sp. Plate III., figs. 56 to 59 ; Plate IV., figs. GO to 66. 



Description of adult Female. Total length, 4 - 4 millims. (fig. 56) : 



Carapace nearly 3|- times in total length, moderately compressed. The dorsal edge 

 very slightly arched, keeled anteriorly where there is a shallow depression on either 

 side, and having a more faintly marked double keel posteriorly. The junction of 

 the median with the double keel is marked by a shallow pit. Pseudorostrum 

 truncated, the ocular lobe reaching quite to the tip. Antennal notch narrow, 

 antenna] tooth sub-acute. Ocular lobe moderately large, not longer than broad, 

 somewhat projecting dorsally ; eye well pigmented, corneal lenses indistinctly 

 deHned. Sides of carapace smooth, with a faint pitting over the whole surface. 



First leg-bearing somite well exposed in adult (in the young female, as in the male, 

 it is wholly concealed). Second somite slightly crested dorsally. 



Abdomen rather slender, a little longer than the cephalothoracic region, the 

 somites sub-cylindrical, with well developed lateral articular processes. 



Antennules (fig. 58) having the first segment of peduncle longer than the other 

 two together, the second a little shorter than the third. External flagellum of two 

 segments, internal flagellum not observed in the specimen dissected. 



Antenna (fig. 59) produced into a narrow process defined by a distinct suture-line. 

 Two plumose seta? on basal part. 



The mouth -parts are normal. 



The first legs (fig. 60) extend a little way beyond the pseudorostrum. The basis is 

 rather narrow, and is equal in length to the remaining segments together. At its 

 distal end, on the side which in the natural position of the limb is ventral, it is 

 produced into a stout tooth which reaches to the end of the next segment. The 

 morns and carpus are somewhat expanded, and the carpus, propodus, and dactylus 

 are of equal length. 



The second legs (fig. 62) have the ischium distinct, the carpus hardly more than 

 half the length of the merus and little longer than the propodus. The dactylus is 

 shorter than the two preceding segments together and bears three unequal spines at 

 the tip. In the remaining legs (fig. 63) the carpus is sub-equal to the merus. 



The uropods (fig. 65) are rather slender, the peduncle about lfths the length of 

 the last somite, and equal to the length of the sub-equal rami. Both rami are acutely 

 pointed, without terminal spines, and the endopod bears a series of about six spinules 

 on the middle third of its inner edge. 



The last two or three thoracic somites are always more or less pigmented. 



Adult Male. Total length, 4'3 millims. (fig. 57) : 



The carapace resembles in shape that of the female, but is less deep. The ocular 

 lobe is more prominent dorsally and the corneal lenses are large and consjjicuous. 

 The antennal notch is shallow and widely open. On the surface of the carapace the 

 dorsal keels and depressions are only faintly indicated. Abdominal somites, as usual, 

 much stouter, and the whole abdomen longer than the cephalothorax. 



7, 2 



