1g10.] J. R. HENDERSON & G. MatTruar: Freshwater Prawns. 283 
P. MALCOLMSONII, H. Milne-Edwards. 
(Pl. xv, figs. 2a—f.) 
P. malcolmsonii, H. Milne-Edwards in Jacquemont’s ‘‘ Voyage 
dans l’Inde,”’ Crustacés, p. 8, pl. iii (1844). 
P. danae, Nobili, Boll. Mus. Zool. di Torino, vol. xviii, n. 452, 
P. 7 (1903). 
Characters of adult males.—The rostrum projects beyond the 
antennular stalk for about one-fifth of its length. Its upper 
margin consists of a toothed highly convex proximal part, and a 
much shorter more or less straight distal part, which carries only 
one or two teeth near the apex. The proximal portion is rela- 
tively deep, while the terminal portion is much narrower. ‘The 
OOtk | b.OlnZ LOE ROM Te sal 
tO 6 
As in P.carcinus the first three upper teeth or rarely the first 
two are on the carapace. 
The large chelipedes, which are sub-equal in length, resemble 
those of P. carcinus, but the spinules are not so strongly devel- 
oped, and are more closely set; the movable finger is somewhat 
less pubescent ; the chelipedes are less than double the body-length. 
A groove traverses both the upper and lower surfaces of the 
palm and carpus, recalling the longitudinal lines visible in P. 
carcinus. ‘The following measurements are taken from the cheli- 
pede of an adult specimen (dried) measuring I91 mm_ in total 
length ;— 
iced 4s aitie Gib. es OS arpa Coy si od bs). 
From the above measurements, it will be seen that the ischium 
and fingers are both relatively shorter than in adult males of P. 
carcinus. 
The telson-tip, as in P. carcinus, is acutely pointed. The 
inner sub-terminal spinule on each side projects backwards beyond 
the outer one, but does not nearly reach the telson-tip. 
The anterior surface of the carapace, the postero-ventral re- 
gions of the first five abdominal epimera, the anterior region of the 
second abdominal epimeron and sometimes of the first, fifth and 
sixth abdominal terga, and the upper surface of the telson are scab- 
rous. The thoracic legs, with the exception of their dactyli, are 
provided with very numerous closely set spinules. 
Characters of females.—The rostrum may be slightly upturned 
distally, and extends as far as, or a little beyond, the distal margin 
of the antennal squame ; sometimes the upper penultimate tooth 
is midway between the ultimate and antepenultimate teeth. 
The large chelipedes are scabrous, and are about two-thirds 
the length of the body. The palm is slightly compressed dorso- 
ventrally, and is of uniform width; it is as wide as, or slightly 
wider than, the distal end of the carpus. The mobile finger is not 
pubescent. The grooves on the carpus and palm which are charac- 
tooth formula is (most commonly 
