4 The Malacostraca of Natal 
transverse ridges of the pleon, and from de Haan’s P. laciniatus by 
differences in the chelipeds. 
A deep longitudinal boat-shaped furrow leads from the rostrum to 
the first of three successive uplifted tubercles, the last of which is in 
a line with the outstanding process ending the antero-lateral margin. 
This process is preceded by a convex row of seven tubercles. On the 
branchial regions irregular rows of tubercles are directed towards the 
process above-mentioned, and towards the following somewhat smaller 
process of the postero-lateral margin. A third process is much smaller 
than the two preceding, but much larger than any which follow. The 
carapace thus shows much resemblance to that of Lambrus tumidus, 
Lanchester, 1900. 
The hand of the cheliped shows near agreement with that whicl 
Miss Rathbun describes for P. serratus, “‘outer margin cut into 
triangular, sharp teeth, of which nine, alternately large and small, are 
on the hand, teeth of inner margin smaller and more numerous (15 or 
16 on the hand).” From the latter carina in our specimen, separated 
by a deep groove but parallel with it, is a third irregularly toothed, 
while between the two margins which agree with Miss Rathbun’s 
description runs a series of very small tubercles along the top of the 
very slightly raised surface. The small ambulatory limbs have little 
spaced tubercles on the fourth and fifth joints, and like the carapace, 
pleon, and chelipeds are moderately setose. The pleopods are long and 
slender. The third segment of the pleon is the widest, slightly wider 
than the second. The telson has a single dorsal tubercle. 
In the mandibles the third joint of the palp is the longest. In the 
first maxille the first joint of the palp is remarkably broad, with a 
second joint subequal in length but much narrower, tipped with two 
short spines. The third maxillipeds have the third joint long and 
broad, with tubereulate edges and a surface row of tubercles near the 
outer margin; the fourth joint is nearly as broad but much shorter, 
and has the short palp inserted in a notch of its distal margin. 
The carapace of the specimen, a female, measures 15 mm. in length 
by 20 mm. in breadth. As preserved, the ambulatory limbs are banded 
with red. The general colour of the living animal recorded by Mr. 
Bell Marley was ‘‘ pale stone grey.” 
Locality. Rock-pool, Durban Bay. 
Trine CYCLOMETOPA. 
See Ann. 8. Afr. Mus., vol. vi, p. 2938, 1910. 
