202 Annals of the South African Museum. 



subacute points bearing 2-3 minute setules, inner margin of inner, and 

 outer margin of outer ramus with 3 small spines. 



Length : Up to 17 mm. 



Colour : Uniform pink, rai-ely claret, eyes black. 



Locality : Sea Point, near Cape Town. 29/11/13. (K.H.B.) cJ 

 and ovigerous ? ? amongst the roots of EcMonia growing on rocks 

 at low water; Woodstock beach, Cape Town. 19/6/14. (K.H.B.) 

 (S.A.M. Nos. A2889 and A2890.) 



The specimens from Saldanha Bay, referred by Chilton to Maera 

 mastersii, seem to belong to this species. Chilton notes their re- 

 semblance to an Elasmopus. 



GEN. GAMMAKUS Fabricius. 



1775. Gammarus (part) Fabricius, Syst. Ent. p. 418. 

 1906. Stebbing, Das Tierreich, 21, pp. 460, 733. 



1909. G. Smith, Tr. Linn. Soc. Lond. ser. 2, vol. 11, pt. 4, 



p. 76. 



1910. Kuiikel, Tr. Conn. Ac. vol. 16, p. 59. 



1912. Sexton, Proc. Zool. Soc. Lond. 1912, p. 657. 



1913. Pearse, Proc. U.S. Nat. Mus. vol. 45, p. 571. 



The only Gammarus hitherto recorded from South Africa is the 

 European and Indian G. pulex. Krauss mentions that it was found 

 in brackish water, and on this account Stebbing (Gen. Cat. S.A. Crust, 

 p. 456) regards the correctness of the identification as very doubtful. 

 No mention of the occurrence of the genus in South Africa has since 

 been made. 



The following 4 species ai-e all foiind within the Cape Peninsula, 

 and the differentiation is probably the result of long isolation. Up 

 to the present no specimens have been collected in other districts (if we 

 except Krauss' specimens), but it is probable that they will be when a 

 proper search is instituted. 



The 4 South African species fall into two sharply marked divisions: 

 1. With the 4th side-plate with a posterior produced angle and the 

 margin above concave, as in the Northern species ; and 2. With the 

 4th side-plate subrectangular and similar to the 'preceding side-plates. 

 This latter form of side-plate 4 is unknown among the representatives 

 from the Northern hemisphere, but it is noteworthy that among the 

 Australasian species of the genus there is one belonging to the second 

 group, namely, G. ripensis Smith 1909, from Tasmania. 



