362 DE. W. T. CALMAN ON NEW OE EAEE 



These lateral setae are always thickly encrusted with mud, and as they project 

 horizontally they greatly increase the apparent breadth and flatness of the body. 



The antennule resembles closely that of Namiastacus unguiculatus, but the third 

 segment of the peduncle is longer than the second, and only two segments could 

 be detected in the outer fiagellum. The antenna has the conical tip more produced 

 than in the species named, and the basal part has two teeth on its anterior margin. 



The mouth-parts resemble those of N. unguiculatus, except in trivial details. The 

 third maxillipeds have a well-developed exopod, and have the carpus and propodus 

 somewhat broadened. 



The first legs are relatively longer than in N. unguiculatus. The basis is about 

 two-fifths as long as the distal segments together. No teeth could be detected on the 

 outer edge of the basis, ischium, or merus. In the second legs the distal segments 

 are a little stouter than in the species named, and there are no conspicuous teeth 

 on the outer edge of the basis. 



The last three pairs of legs are much stouter and shorter than in N. unguiculatus. 

 In the third pair the basis is about two-thirds as long as the distal segments together, 

 the carpus is hardly longer than the merus and shorter than the propodus. In the 

 fifth pair the basis is more than half as long as the distal segments together ; the 

 carpus is about one-half longer than the merus and about equal to the propodus ; the 

 dactylus, with its claw, is about equal to the propodus. 



The uropods have the peduncle a little longer than the last somite, slightly expanded 

 distally, with three conspicuous teeth on the inner edge. The endopod is a little 

 longer than the peduncle, with a strong terminal spine a little longer than the ramus 

 itself and a shorter spine near the distal end of the inner edge. The exopod is more 

 than three-fourths as long as the endopod, with a long and slender terminal spine. 



Occurrence. — Gulf of Siam, " Koh Kahdat, about 1 fathom, coral." Th. Mortenseu 

 Coll., Copenhagen Museum. Co-types in British Museum. 



ScHizoTRKMA BiFRONS, sp. n. (Plate XXXIV. figs. 18-21.) 



Description of adult Female. — Total length I'Qo mm. 

 ■ The carapace is a little less than two-fifths of the total length, its height not more 

 than two-thirds of its greatest width. The pseudorostrum, seen from the side, is very 

 short and rounded, with a group of curved spines on its lower edge ; seen from above, 

 the two parts of the pseudorostrum surrounding the respiratory orifices are widely 

 separated ; the branchial siphons are long. The antero-lateral margin slopes back- 

 wards from the lower edge of the pseudorostrum, and a widely open and angular 

 antennal notch is completed below by the antero-lateral angle, which is produced as 

 a stout cylindrical process tipped with a curved spine ; a row of small spines on the 

 outer surface of this process runs backwards on to the side of the carapace. The 

 darkly pigmented eyes, each with three cornedl facets, lie just behind the respiratory 



