PYCNOGONIBA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 175 



as the other two together ; all are fairly uniformly covered with short setae ; the distal 

 fringe of the third is, however, ventral and composed of numerous long slender setae, and 

 these are most conspicuously developed on the two posterior pairs of legs of the male 

 — obviously a sexual character. The three following joints differ but little, their pro- 

 portions being 6'5, 7, 7'25 ; the tarsus and propodus being as 3 to 2 - 5. The terminal 

 claw is rather slender, and is accompanied by two auxiliaries less than half its size. 

 The limb is thickly covered with setae of no great size, but variable in length ; they 

 are longer and stronger laterally than elsewhere. This is not so conspicuous on the 

 femur as on the tibiae ; they are largest on the second tibia, though the general covering 

 of this joint is much finer than on the preceding joints. On the tarsus and propodus 

 the setae are small, uniform in size, and thickly set. The distal fringe of the femur is 

 dorsal and composed of long stiff setae ; that of the first tibia is ventral and rather more 

 spinous ; that of the second tibia is also ventral and composed of strong spines. 



The Genital apertures of the male are only to be found on the second coxae of the 

 two posterior pairs of legs ; those of the female occur on every leg. 



Of the enormous number of specimens taken in Scotia Bay, but a few males carry 

 eggs. These are rather large, 0'7 mm., and between thirty and forty in a packet. This 

 is slung over the fifth joint of the oviger by a stout thread near its proximal end. 

 Another specimen carries a very large mass of young. These show the chelae well 

 developed, as are also the first two pairs of legs ; the third pair are conspicuous rudi- 

 ments, and the fourth pair can be seen as a swelling on either side of the abdomen. 

 Rudiments of the palps are visible, and the ocular tubercle is present. Scotia Bay, 

 about 10 fathoms. Burdwood Bank, south of the Falkland Islands, one specimen, 

 immature, 56 fathoms. 



Chsetonymphon assimile (Plate I., figs. 1, la). 



Specific Characters. — Body robust, with lateral processes very distinctly separated ; 



devoid of setae but for the distal fringes. 

 Palps five-jointed ; proportions of last three 7 '3, 4, 4. 



Ovigers ten-jointed ; denticulate spines not numerous, with five (?) lateral teeth. 

 Legs with long terminal claw and very minute auxiliaries. 



The Body is stoutly built, with the lateral processes distinctly but not widely 

 separated, and they carry a few stout setae as a distal fringe ; otherwise the body is 

 quite smooth. Segmentation is distinct but not prominent, and the abdomen, which 

 is pyriform and directed upwards to clear the posterior lateral processes, is not articu- 

 lated to the trunk ; it only bears two small setae near its extremity, sometimes more. 



The Cephalon is short, constricted to form a distinct neck, and then expanded to 

 form two diveroent lobes. 



The Ocular tubercle lies between the neck and the first pair of lateral processes as 

 a tall cylindrical structure, having at its rounded summit four well-developed eyes. 



TRANS. ROY. SOC. EDIN., VOL. XLVI. PART I. (NO. 6). 24 



