77 



crossed by the fine but quite distinct cervical groove. It varies in length 

 according to sex and age, being sometimes a little shorter, sometimes a little 

 longer than the rest of the carapace. It is high and nearly straight in its basal 

 third or so, where it is armed dorsal ly with from 6 to 10 (almost always 7) teeth, 

 and is slender and upcurved in its distal two-thirds or so, where it may either 

 be unarmed, or more usually may be armed with one or two teeth : ventrally it 

 is armed in rather more than its middle third with 4 distant teeth. 



A ridge defines the branchial regions superiorly, and a decpish groove 

 separates the hepatic region from the convexity of the efferent branchial canal. 



The outer orbital angle is well defined but blunt, and the post-antennular 

 spine is small : the post-antennal spine is large and obliquely salient, but is not 

 buttressed by a long carina. 



The abdominal terga from the 2nd to the 6th inclusive are sharply carinated : 

 the keel of the 2nd tergum ends abruptly, but those of the 3rd, 4th, 5th, and 

 Oth are produced posteriorly and end each in a sharp tooth of no great size, that 

 of the 3rd, which is conspicuously the lai'gest, not reaching to the middle of the 

 4th somite, and that of the 6th being next in size. The keel of the 4th tergum 

 has a fine notch in its posterior fourth. The 6th abdominal somite is not half 

 again as long as the 5th. The telson is slightly longer than the endopoditc, 

 but considerably shorter than the exopodite of the caudal swimmeret. 



Eyes a little wider than their stalks, dark brown or nearly black in colour. 



The antennular peduncle does not reach halfway along the antennal scale ; 

 its basal joint, which is the longest, has a small tooth at the distal end of the 

 outer border. 



The antennal scale is about two-thirds the length of the carapace without 

 the rostrum, its outer border is broadly strengthened and ends in a small spine. 

 The ventral border of the 2nd joint of the antennal peduncle is produced to 

 form a stout spine, which is fringed internally with long seta?. 



The external maxillipeds reach about three-quarters of the way along the 

 antennal scale. The 2nd pair of legs, which are slightly longer and slenderer 

 than the 1st pair, reach a little more than halfway along the antennal scale. 

 The third pair of legs, which are the longest, reach nearly to the tip of the 

 antennal scale. In the 3rd and 4th pair of legs the posterior border of the 

 ischium and merus is closely spinose, the posterior border of the propodite has 

 some fine deciduous spinelets, and the posterior border of the very short 

 dactylus has a comb- of capillary spinelets. In the 5th pair of legs the posterior 

 border of the merus has a feAV small spines, the distal two-thirds of the posterior 

 border of the propodite is fringed with a brush of seta 1 , and the minute dactylus 

 is hidden in a tuft of setae. 



Colour in life crimson. 



