37 



is certainly a mistake to say that it occurs in the rivers of the 

 Colony, where so far as I can make out no such Crustacean 

 occurs. I have learned that it is also found in Algoa Bay." 



The small apical tooth of the rostrum reaches beyond the 

 base of the third joint of the peduncle of the first antennae, 

 the sides of the rostrum are serrate with five, six or seven 

 points, all small and diminishing- successively backward ; it 

 is without teeth on the lower surface ; on either side there is 

 a small tooth a little way behind the margin of the orbit. 

 The carapace, rostrum included, in the male is shorter than 

 the pleon ; its sides and the back of the telson are hirsute and 

 there are scattered hairs at various parts of the whole back ; 

 the female specimen is much less hairy than the male. The 

 lower margins of the pleon segments are closely fringed with 

 hairs, and they are shaped nearly as in Astacus gainmarus, 

 the common lobster. The telson is longer than broad, the 

 slightly sinuous sides converging very little to the pair of 

 denticles which flank the broad apical convexity. The short 

 stout eyes, black in spirit, reach about half-way along the 

 rostrum. The first antennae are about two-thirds the total 

 length of the carapace, their two flagella nearly equal in 

 length. The second antennae are as in Astacus gammarus, 

 and when bent back reach the extremity of the body. The 

 elongate hairy third maxillipeds differ a little from those of 

 the species just mentioned in the marginal denticulation. In 

 the chelipeds the fourth joint has a hairy fringe ; the fifth 

 besides being hirsute has three or four lines of tubercles, not 

 all very regular or distinct ; the sixth which is very much 

 longer than broad, and is rather broader in the right limb 

 than the left, besides the hairy covering on the outer surface 

 which extends over the base of the thumb, has the outer 

 margin delicately serrate, and the inner conspicuously ; the 

 thumb and finger of the larger chela are much shorter than 

 the trunk of the joint, the bent apices crossing, the marginal 

 teeth few and not bulky, hairs at the base of the thumb 

 partly filling the cavity between it and the finger ; in the 

 narrower chela the thumb and finger are not much shorter 

 than the trunk of the joint, nearly approximate, with many 

 minute but unequal teeth and a long brush of hairs. The 

 fourth and fifth legs have the finger subequal in length to 

 that which assists in forming the chela of the second and 

 third pairs, but it is less hairy. In the fifth pair there is a 

 tuft of hairs at the apex of the sixth joint which in a dried 

 specimen might go some way towards producing the false 

 impression of a chela. This limb has a branchia as in the 

 common lobster. In Huxley's "Crayfish," p. 265, there is a 

 perplexing statement that " in the lobster, the solitary 



