26 Memoirs of the Indian Museum. [Voi,. IV, 



convergent posteriorly and the intermediates more or less curved inwards. The follow- 

 ing abdominal carinae end in spines l : — ■ 



Carinae. Abdominal somites. 



Submediati . . • • • • 6. 



Intermediate .. •• •• 5> 6. 



Lateral , . . • • • 5.6. 



Marginal .. .. .. (2) (3) 4, 5. 



The telson (figs. 1, 2) is considerably broader than long and is strongly convex 

 dorsally. The median carina is distinct, very obscurely notched at the base, and in 

 most cases terminates in a short spine ; on either side of it there are a number of 

 ridges which are usually broken up into tubercles. Close to the median carina on each 

 side a row of from three to six tubercles is usually found, the two rows converging 

 posteriorly and meeting in a small tubercle immediately behind the distal end of 

 the carina. Beyond this there are a number of oblique ridges — in some cases very 

 obscure, in others sharp and broken up into a series of tubercles — and, in addition, 

 several isolated tubercles or transverse tuberculate ridges may usually be seen close to 

 the proximal margin. The six marginal teeth are acute but short ; the submedian pair 

 is provided with minute movable tips, but these in most well-grown specimens are 

 broken off. The outer edges of at least the intermediate pair are serrate and a small 

 blunt praelateral lobe is usually distinct. There are one or two pairs of submedian 

 denticles, four to seven intermediate, and one lateral, and these like the primary teeth 

 frequently possess serrate margins. The ventral surface of the telson is quite smooth 

 except for a short, but well-marked, post- anal crest. 



In adult males (fig. 2) the median carina is rather more swollen than in the female 

 (fig. 1) and there is an enormously inflated triangular swelling at the base of each mar- 

 ginal tooth. The tubercles, moreover, are generally more rounded and less conspicuous 

 than is the case in the other sex. 



Wood-Mason (1895, pi. iv, figs. 8, 12) has given two figures of the telson of this 

 species and two additional figures will be found on PI. I, figs. 1 and 2. The latter, 

 which were drawn from specimens obtained in the Persian Gulf, differ considerably 

 from the more normal types figured by Wood-Mason, that of the female, in particular, 

 showing quite an extreme tubercular development. 



The peduncular segment of the outer uropod (figs. 1, 2) is provided with a single 

 dorsal spine near its articulation with the exopodite. The inner spine of the ventral 

 bifurcate process is more than twice the length of the outer and bears a well-developed 

 lobe on its external aspect. Internally the process is armed with five to eight sharp 

 spines. The spines on the outer margin of the basal segment of the exopod are flat- 

 tened and curved and the ultimate is fully two and a half times as long as the next of 

 the series. 



1 This tabular method has been adopted for showing the position of the spines on the abdominal 

 somites. Numbers in brackets indicate that spines occur on these somites in some specimens, but not 

 in all. (See p. 9.) 



