202 PROFESSOR CHARLES CHILTON ON THE 



The third uropod reaches a little beyond the peduncle of the second ; its single branch 

 is about as long as the peduncle, but rather more slender, and bears a minute second 

 joint. The telson reaches slightly beyond the third uropod, is greatly flattened 

 vertically, and has the dorsal border somewhat thickened, as described in T. walkeri. 



In many respects this species shows close approximation to T. herdmani, described 

 by Mr WALKER, from South Victoria Land, but is clearly distinguished by the large 

 chelate second gnathopod. This may, however, ultimately prove to be a sexual 

 character. 



Thaumatclson herdmani Walker. 



Thaumatelson herdmani Walker, 1906, p. 15, and 1907, p. 21, pi. vii. fig. 11. 

 South Orkneys, Scotia Bay, Station 325. 1 903. A few specimens. 



After 1 had drawn up the description of the preceding species, with the remarks 

 thereon, I found in the " residues " of some collections made during 1903 both additional 

 specimens of that species and also others with subchelate second gnathopoda agreeing 

 in all respects with T. herdmani Walker, so that that species also does occur at Scotia 

 Bay. I can find very little difference between the two except in the second gnathopoda, 

 and, as stated above, strongly suspect that both forms belong to the same species ; but 

 the additional specimens came into my hands too late to allow of the question being 



fully investigated. 



Genus BIRCENNA Chilton, 1884. 



Bircenna crassipes (Chevreux). 



Wandelia crassipes Chevreux, 1 906A, p. 87, figs. 1 and 2. 



1906U, p. 45, figs. 24-26. 

 Bircenna crassipes Cliiltou, 19u9is, p. 62. 



South Orkneys, Scotia Bay, Station 325; dredge, 9-10 fathoms. May 1903. 

 One specimen, 2 mm. long. 



This small specimen agrees very closely with CHEVREUX'S description and figures. 



The species is very close to B. fulva Chilton from New Zealand, and differs from it 

 only in the longer and more slender gnathopods, and in having the branches of the 

 first and second uropods equal and shorter in proportion to the peduncles. 



Kuria longimana Walker and Scott (1903, p. 228), from the Indian Ocean, appears 

 to be nearest ally of the genus Bircenna. 



Genus COLOMASTIX E. Grube, 1861. 



Colomastix brazieri Haswell. 



Colomaftix brazieri Haswell, 1880, p. 341, pi. xxii. fig. 4. 

 Stebbing, 1906, p. 206. 



South Orkneys, Scotia Bay, Station 325. 1903. Two small females, the larger 



3 '5 mm. long. 



These specimens certainly belong to this genus, and probably to HASWELL'S species ; 



(ROY. soc. KDIN. TRANS., VOL. XLVIII., 484.) 



