Contributions to the Crustacean Fauna of South Africa. 413 



GEN. EHABDOMESUS Eich. 



1886. Ischnosoma (part) Beddard, Challeug. Eep. vol. 17, p. 39. 

 1908. Kludiilomesus Eichardson, Proc. U.S. Nat. Mus. vol. 35 [1909], 



p. 81. 

 1914. Vanhoffen, Deutsche Siidpol. Exp. vol. 15, pt. 4, 



p. 560. 



The " Challenger " obtained two species of this interesting genus 

 in the Southern oceans: R. bacillus (Bedd.) from 1800 fathoms off 

 Melbourne and R. bacilloides (Bedd.) from 1450 fathoms off Valparaiso. 

 There was only one specimen of each species and both were fragmentary. 

 Great interest therefore attaches to the two specimens in the " Pieter 

 Faure " Collection, not only because they are from a new locality but 

 mainly because they are complete except for the long and extremely 

 slender peraeopods and 2nd antennae. A description of the mouth- 

 parts can therefore be given and Beddard's. description of the pleopods 

 confirmed. 



The only example since obtained is R. inermis, taken by the " Gauss " 

 in the Antarctic Ocean. 



EHABDOMESUS BACILLOPSIS n. sp. 

 (Plate XVII. Fig. 13.) 



Male. Body very elongate, glabrous. Head broader than long, 

 somewhat immersed in the 1st peraeou segment, anterior margin 

 slightly convex. Peraeon segment 1 shorter than 2, its lateral parts 

 directed forwards and embracing the base of the head. Segments 2 and 

 3 subequal, the lateral portions prominent and rounded. Segment 4 

 anteriorly similar to 3, the posterior portion much narrowed, elongate, 

 cylindrical, the whole segment a little longer than segments 1-3 

 together. Segment 5 longer than 4, anteriorly narrow and cylindrical, 

 posteriorly widening, the lateral portions directed backwards. Segments 

 6 and 7 subequal, a little shorter than 2 or 3. All the segments, 

 including 7, bear on the lateral portion a strong spiniform projection 

 which is curved forwards on the anterior 4 segments, backwards on 

 the 3 posterior ones. 



Pleou segment 1 very short and narrower than segment 2, which is 

 shield-like, ovate, apically rounded. 



Antenna 1 reaching back to 3rd peraeou segment, basal joint some- 

 what triangular, followed by one very slender, elongate and strongly 

 indurated joint, flagellum still more slender, shorter than the preceding 

 long joint, 4-joiuted, ending in 2 long unequal setae. 



Antenna 2 broken off at the 3rd joint in both specimens. 



