Crustacea Decapoda and Stomatopoda. 281 



extend throughout the anterior two-thirds of the lower border, or may cease some 

 Httle distance behind the apex. 



The cornea is proportionately larger than in any C. nilotica that I have seen, 

 while the stalk is shorter and broader. In dorsal view the length of the cornea is 

 greater than that of the stalk, whereas in C. nilotica subsp. gracilipes the reverse is the 

 case. 



The preocular length of the antennular peduncle is at least 0-82 times the post- 

 ocular length of the carapace. The lateral process is short, not reaching the end of 

 the basal segment. The antennal scale is from 3-6 to 3"8 times as long as broad ; the 

 second segment of the antennal peduncle is produced distally as a spine immediately 

 below the insertion of the scale. 



The carpus of the first peraeopods (text-fig. loè) is about 2-2 times as long as 

 broad in the Patani R. specimens, from 2-4 to 2-6 times in those from Penang. The 

 fingers are about 1-5 times the length of the palm.' 



In the second peraeopods (text-fig. loc) the carpus is one quarter longer than the 

 chela and is from 4-9 to 5-8 times as long as broad. The fingers are about 1-5 times 

 the length of the palm.' 



The last three pairs of peraeopods usually bear from 2 to 4 spines on the lower 

 edge of the merus and, occasionally, one near the distal end of the carpus. The pro- 

 podus of the third pair (text-fig. xod) is from 5-6 to 6-6 times as long as the total length 

 of the dactylus in the Patani R. specimens, from 5*5 to 5*8 (exceptionally 5-1) times 

 in the case of those from Penang. Excluding the spines, which vary in number from 

 5 to 7, the dactylus (text-fig. zoe) is from 2'0 to 2-6 times as long as broad. In the fifth 

 peraeopods (text-figs. 10/, g) the propodus is from 4-8 to 6-8 times the length of the 

 dactylus ; the dactylus is from 2-5 to 2-8 times as long as broad and bears from 29 to 

 43 (usually 36 to 43) spinules. 



There are from 3 to 5 pairs of dorsal spines on the telson and from 8 to 10 at the 

 apex. On the outer uropod there are from 12 to 14 movable spines. 



The eggs vary from 0-35 to 0-42 mm. in length and from 0"22 to 0-25 mm. in 

 breadth ; they do not differ in size in specimens from the two localities. 



Large specimens reach a length of about 28 mm. In examples of 18 to 20 mm. 

 in length the rostrum is not longer than in adults whereas in varieties of C. nilotica it 

 is proportionately longest in adolescent individuals. 



The subspecies peninsularis is based solely on the character of the upper border of 

 the rostrum ; in the subspecies the teeth extend along the whole length of this border, 

 whereas in the typical form there is an untoothed portion close behind the apex. 



The few Patani specimens were obtained in the river in muddy water which was 

 fresh though subject to tidal influence, while those from Penang came from a stream 

 of clear water in the Botanic Gardens. In the latter locality they occurred in places 

 where the flow of water was not very rapid and where the banks were not overgrown 



1 The length of the palm is measured from the hindmost limit of the chela to the dorsal point of junction between 

 palm and dactylus, the dactylus from its tip to the same point. De Man appears to have measured these segments 

 difiEerently. 



