386 Annals of the South African Museum. 



confirmed Sars' report of the presence of a process in A. dilatata 

 and also in Arcturus baffini ; " but it is so small in the latter case 

 that it can hardly be regarded as of systematic importance" (Caiman 

 in litt. 31/7/16). Caiman states that it is absent in Antarcturm 

 antarcticus and meridionalis. It is also absent in the specimens I 

 described in 1914 as the male of Antarcturus kladoplioros Stebb., in 

 Astacilla bacillus n. sp. and in the only two of the new species assigned 

 to Arcturella of which the male is known. 



It seems, therefore, that no great importance can be attached to the 

 presence or absence of such a process, and that it cannot be used to 

 delimit the genera in this family. But its presence in Arcturella 

 dilatata renders unnecessary the genus Arcturopsis, which must 

 therefore sink into synonymy. 



But Koehler described one species in which the process was on the 

 fifth segment namely, A. melitensis ; he did not, however, think that 

 a new genus was necessary for this species and so placed it in 

 Arcturopsis. On the contrary, I think he might well have instituted 

 another genus for it, and I propose here, since Arcturopsis, void ab 

 iuitio, cannot be used, the name 



ARCTOPSIS u.g. 



Like Arcturella Sars, but with a ventral process on the fifth peraeon 

 segment in the male. 



One species : A. melitensis (Koehler) 1911. 



GEN. ASTACILLA Cordiner. 



1795. Astacilla Cordmer, Singular Subjects of Nat. Hist. sect. 



Astacillae. 



1893. Stebbing, Hist. Crust, p. 370. 



1897. Sars, Crust, Norw. vol. 2, p. 87. 



1901. Ohlin, Svenska Exp. Magellan, vol. 2, p. 266. 



1905. Stebbing in Herdmau's Ceylon Pearl Fish. Suppl. 



Eep. 23, p. 46. 



1905. Eichardson, Bull. U.S. Nat. Mus. No. 54, p. 323. 

 1911. Koehler, Bull. lust. oc. Monaco, No. 214, pp. 1, 44, 



etc. 

 1914. Yanhoffeu, Deutsche Siidpol. Exp. vol. 15, pt. 4, p. 523. 



ASTACILLA BACILLUS n. sp. 



Body perfectly smooth, non-granular, nonsetose. Limits of head 

 and peraeon segment 1 scarcely visible. Eyes horizontally pear- 



