200 Annals of the South African Museum. 



Marsupial pouches arising from bases of peraeopods 3, and 

 extending from segment 4 to segment 7. 



First and second pleopods, outer margin of peduncle with 

 5 plumose setae, inner rarnus smaller than outer with 3 plumose 

 setae on its inner margin (away from outer ram us) and an apical 

 spine-seta. 



Third pleopods similar, but peduncle has only 2 setae, and inner 

 ramus only 1 seta. 



Uropods as long as last 3 pleon segments combined, 6-pointed, 

 the 1st joint considerably stouter than the rest, 6th joint minute, 

 with long terminal setae. 



Length : 5'5 mm. 



Colour : Whitish with slaty-grey mottlings, the head and a medio- 

 dorsal spot on the peraeon segments markedly darker than the rest 

 of the body. 



Locality : St. James, False Bay. 29/4/12. (Coll. K.H.B.) In 

 holes in encrusting sponges (Halichondria) and compound Ascidians, 

 low tide. $ $ and ? ? (with ova). (S.A.M. No. A2105.) 



This species belongs to Tanais sensu lato, in that it has 6 pleon 

 segments and not 5 as in Tanais sensu stricto (Sars, 1896). In general 

 shape and the possession of 6-jointed uropods it resembles most 

 nearly T. normani, Eichardson, 1905, but differs in the form of the 

 first gnathopods of the male : T. normani has the finger and 

 thumb not widely separated (i.e., the finger is not strongly curved), 

 whereas in T. spongicola they are widely separated, as is the case in 

 T. robustis, Moore, 1894. The 6-jointed uropods distinguish it also 

 from T. gracilis, Heller, 1866. 



FAMILY GNATHIIDAE. 



1880. Gnathiidae, Harger, Eep. U.S. Cornm. Fish. pt. 6, 



p. 408. 



1886. Anceidae, Beddard, Challenger Eep. vol. 17, p. 135. 

 1897(-1899). Gnathiidae, G. O. Sars, Crust. Norw. ii. p. 50. 

 1901. Gnathiidae, Dollfus, Bull. Soc. Zool. France, xxvi. p. 240. 

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



p. 55. 



1909. id. Proc. U.S. Nat. Mus. vol. 35, p. 483. 



1913. ,, Stebbing, Trans. Zool. Soc. London, vol. 20, pt. 4, 



p. 231. 



