20 CRUSTACEA MALACOSTRACA. II. 



II. Neotanais giganteus n. sp. 

 (PI. II, figs. 2 a— 2 h.) 



Adult Male. Carapace nearly a.s long as the three following segments combined, seen from 

 above peculiarly shaped (fig. 2 a), as scarcely its front half has the lateral margins feebly convex and 

 is only a little longer than broad, while the major posterior part is laterally considerably expanded, 

 but the postero-lateral area of this part is subquadrangular, well marked off by a suture and must be 

 considered the coxal joint of the chelipeds. A portion of each lateral margin somewhat behind the 

 front angle is furnished with a close row of outstanding, stiff setae (fig. 2b). 



The ocular plate is well marked off (fig. 2 c), nearly ovate, with the end subacute and without 

 any vestige of visual elements. — The antennulfe (fig. 2 b) are somewhat longer than the carapace, 

 7-jointed; the first joint is very long, as long as the other joints combined, seen from above with the 

 inner margin straight, the major proximal part of the outer margin distinctly concave, but the distal 

 part of this margin somewhat convex and bearing a close longitudinal row of horizontal, stiff setse. 

 Second joint almost as thick, but somewhat less than half as long, as the first, with a shorter row of 

 stiff, horizontal setae on the outer margin. Third joint is short and rather thick; fourth joint is some- 

 what shorter than the second, tapers much towards the end and has on the outer side a long row of 

 long sensory hairs; fifth and sixth joints, and especially the last-named, are short, and seventh joint is 

 extremely short. — The antennte (fig. 2 c) 9-jointed; second, fourth and fifth joints long; third joint a 

 little longer than deep; sixth joint a little shorter and considerably thinner than the fifth; seventh and 

 especially eighth joint somewhat shorter and thinner than the sixth, and ninth joint short and very thin. 



The chelipeds (fig. 2 d) are robust. The coxal joint is mentioned above. The basal joint is 

 moderately short but extremely thick, its whole lower side being produced downwards as a long, thick 

 and rounded protuberance. The carpus is long, almost three times as long as deep, and the proximal 

 third of its lower margin is deeply concave. The chela is a little longer than the carpus, two and a 

 half times as long as broad; the movable finger, which is much curved near the middle and somewhat 

 shorter than the strongly convex anterior margin of the hand, has almost the proximal half of its 

 incisive margin serrate and a strong, triangular tooth considerably beyond the middle. The fixed 

 finger has on the incisive margin near its middle a long, straight, subcylindrical, distally rounded pro- 

 cess, and near the base a broad protuberance with two small incisions. The fingers cross each other 

 greatly, while a large interval is left between their major proximal part. 



The thoracic segments subsimilar in shape, length and breadth (fig. 2 a), excepting the seventh 

 segment which is somewhat shorter; the lateral margins of the segments are ver)- convex. — The 

 legs are moderately slender and somewhat long, all subsimilar, the only exception being that the real 

 claw is extremely short on the anterior pairs (fig. 2 f), a little longer on the posterior pairs (fig. 2 g). 

 Third joint is extremely short, fifth joint a little longer than the fourth, a little shorter than the sixth 

 (fig. 2 e), and the distal half of its lower side is furnished with a number of setse; sixth joint has the 

 distal half of the lower margin and the end set with a good number of setse; seventh joint with claw 

 much shorter than sixth joint. 



The abdomen as long as the sum of the four preceding segments; its four anterior segments 

 are broader than the thorax; the pleopods are strongly developed. Sixth segment not quite as long 



