68 "TERRA NOVA" EXPEDITION. 



lu the male sex, the second coxa of the penultimate leg has the posterior corner, which 

 bears the openings of the cement-glands, slightly produced as a round knob, in striking 

 contrast to the long process found in this position in R. mediterraneus. 



Genus PYCNOGONUM, Briinnich. 



Pycnogonum gaini, Bouvier (Text-fig. 22). 

 P. gaini, Bouvier, 1910, p. 30; id., 1913, p. 156, text-figs. 101-104. 

 Occurrence. — Station 220, off Cape Adare, 45-50 fathoms ; 1 young. Station 314, 

 McMurdo Sound, 222-241 fathoms ; 2 $. Station 338, Entrance to McMurdo Sound, 

 207 fathoms; 3 ^, 1 ?. Station 340, off Granite Harbour, 160 fathoms; 1 ^. Station 

 355, McMurdo Sound, 300 fathoms ; 1 ?. 



Remarks. — This species, described by Bouvier from a single female specimen, is 

 also represented in the " Gauss " collection. The " Terra Nova " specimens from the 



Koss Sea area complete the record of circumpolar distribution 

 for the species. They agree closely with Bouvier 's account, and 

 the largest is of nearly the same size as that described by him. 

 It is not quite correct, however, to state that the species is " de 

 beaucoup, la plus grande du genre Pycnogonum.'" Sars's and 

 Norman's measurements and the evidence of specimens in this 

 Museum show that P. littorale grows to a similar or even slightly 

 Fig. 22. — Pi/cnogo-num greater size. 

 3am, Bouvier. Oviger r^^^ ^^-g^^.^^ ^^ ^j^^ ^^^^^^ (p-g ^2) are composed of eight 



segments, excludins; the termmal claw, m contrast to those of ". 

 littorale, which have nine.* The penultimate segment is very short, giving the 

 terminal part of the oviger some resemblance to that of the walking legs, with which 

 appendages the oviger also agrees in the total number of its segments. 



* Curiously enough Sars (1891, pp. 8 and 10, PL 1, fig. Ig) attributes only eight segments to the 

 ovigers of P. littorale, and notes that they " have the same number of joints as the ambulatory legs." 

 The ovigers of this species have been correctly described and figured by Hoek (1877, p. 237, PI. xiv, fig. 1), 

 and Wilson (1880 p. 469, PL 1, fig. 3a). 



