45 



beyond the middle, a third spine near the base, and on the right exopod a fourth spine between 

 the two proximal spines. According to the shape of the insertions of these spines and of the 

 serration along the margin no spines are wanting, though the assumption that the entire margin 

 has been set with spines would explain the anomalous arrangement. The distal joint of the 

 exopod is almost three times as long as broad. The telson is proportionately short (fig. 4^), 

 only a little more than twice as long as broad and far from reaching the articulation of the 

 exopod ; the basal somewhat widened part with two pairs of moderately small spines, and the 

 proximal half of the lateral margins has only these two pairs; the distal half (fig. 4c) of each 

 lateral margin with 10 or 11 spines, the 3 proximal of which are moderately small, the 2 or 

 3 next very small, the next spine is a little larger, the following spine very small, and now 

 the spines increase in length to the last lateral spine, which is moderately long; the end of 

 telson is broader than in any preceding species, a little emarginate at the middle and laterally 

 rounded, with 4 pairs of very long spines, and the outer pair of these spines placed half on the 

 terminal, half on the lateral margin and somewhat shorter than the three other pairs; between 

 the inner pair of terminal spines no small spines but only the usual pair of long setse are found. 



Length 6.6 mm. 



Remarks. — This interesting species differs strongly from all other forms hitherto 

 known by the curious serration and spinulation of the proximal joint of the exopod of the uropods 

 and by the shape and terminal spinulation of the telson. Unfortunately no male specimen could 

 be detected, and it may be possible that the male pleopods show features not found in the 

 three other groups of Asiatic species. 



Hemisiriella n. gen. 



This new genus differs from Siriella in the following features. Carapace unusually short, 

 leaving uncovered the two posterior thoracic segments both above and on the sides and besides 

 the upper surface of the antepenultimate segment. Third joint of the antennular peduncle in the 

 female (PI. VI, fig. 1 6) at least twice as long as broad and almost as long as the first. The 

 antennal squama proportionately small, not quite reaching the end of the third joint of the 

 endopod (PI. VI, fig. 1 c). On the left mandible (PI. V, figs. 5^, 5 c and 5 f) the cutting edge 

 is transverse without saw-teeth, the movable lacininia is large, conical, serrated behind, and the 

 molar process is short, transversely cut, broader from above than from below; on the right 

 mandible the cutting lobe is produced as a very large, triangular, acute plate with a single 

 tooth. above near the base (PI. V, figs. %d and 5/), a movable lacinia is wanting, and the 

 molar process is produced, somewhat narrow, a little curved and blunt ; setse or spines are 

 wanting on both mandibles. First pair of thoracic legs (PI. VI, fig. \ g) extremely elongated, 

 nearly twice as long as the second pair (PI. VI, fig. 1 k), with a distinct transverse articulation 

 on sixth joint before the middle and the terminal brush of setse exceedingly long, surrounding 

 the apical and nearly rudimentary part of the leg (PI. VI, fig. 1 //); on the following pairs of 

 thoracic legs an articulation across the sixth joint could not be perceived. 



It may be added that the pseudobranchial rami on second to fourth pairs of pleopods 



