430 Annals of the South African Museum. 



character of Paridotea, I think it legitimate to include clongata in 

 this genus, which will therefore contain the following species : 



Paridotea ungulata (Pallas). Type species. 

 ,, peronii (M. Echv.). 

 ,, elongata (Miers). 

 ,, rubra, n. sp. 

 ,, reticulata, n. sp. 

 ,, , fucicola, n. sp. 



Among the four common Cape specimens, P. ungulata, rubra, 

 reticulata, nud fucicola, I have found no variation in the distinctness 

 of the pleon sutures. 



FAMILY ASTACILLIDAE. 



1908. Astacillidac, Stebbing, S.A. Crust, pt. 4, p. 50. 



1911. Arctnridac, Koehler, Bull. Inst. Ocean. Monaco, No. 214, p. 1. 



1914. Astacillidae, Barnard, Ann. S.A. Mus. vol. x. pt. 7, p. 206. 



IDAECTUEUS, n. gen. 



Body not geniculate, head fused with 1st peraeon segment, all the 

 segments of the pleon fused into one piece, 4th peraeon segment 

 longer than the others in the female only, but not markedly 

 elongate, antennae, mouth parts, peraeopods, pleopods and uropods 

 as in Astacillidae, $ appendage on 7th peraeon segment single, no 

 appendage on 3rd or 5th segments of $ , 3 pairs of marsupial 

 plates. 



This genus forms a transition from the typical Astacillids to the 

 Pseudidoteids and Amcsopus, themselves intermediate between the 

 Astacillidae and Idoteidae. But that it must be placed in the former 

 family and not the Pseudidoteidae or Amesopidae is clearly shown by 

 the appendages, especially the anterior peraeopods. 



IDABCTURUS PLATYSOMA, n. sp. 

 (Plate XXXVII. B.) 



Body flattened, not geniculate, resembling an Idoteid, smooth, 

 glabrous. Head united with 1st peraeon segment, but the sutures 

 distinct laterally, anterior margin excavate, eyes oval, in middle of 

 lateral margins. Peraeon segments 2 and 3 subequal, a little longer 



