PYCNOGONIDA. 63 



the extremity of the femur, and most numerous dorsally ; on the first tibia they 

 increase in size ventrally, and still more so on the second tibia ; on the tarsus and 

 propodus the ventral setae are comparatively long and conspicuous. 



The specimen from which the above description was taken seemed to be an 

 exceptionally spinose individual. Seven specimens were obtained, and in the other 

 six all the features described above can be seen, though to a less degree, when not 

 concealed by a growth of polyzoa. 



Winter Quarters, 12 to 25 fathoms. 



COLOSSENDEIS FRIGIDA. 



(Plate IX., fig. 3 ; Plate X., figs. 5 and 6.) 

 Specific characters : — 



Body smooth, with lateral processes widely separated. Four well-developed eyes. 

 Proboscis approximately twice the length of the trunk, dilated about the centre and quite smooth. 

 Palps, 10-jointed ; eighth joint half the size of the two terminals, which are sub-equal. 

 Ovigers, with a group of four or five irregular rows of special spines in addition to the two 

 primary rows. 



Claws of legs about half the size of the propodus. 



This last character, together with the spines and terminal claws on the ovigers, 

 readily separate this species from C. megalonyx, to which it appears very closely 

 related. 



A considerable amount of latitude must be allowed on the proportions of the 

 joints of the various appendages as a guide to specific discrimination. Thus the 

 proboscis varies in length from 11 mm. to rather more than 21 mm., and the trunk 

 to the base of the abdomen, from rather less than 6 mm. to rather more than 11 mm., 

 but the longest proboscis does not coincide with the longest body. The same sort of 

 variation occurs throughout. 



There is no trace of segmentation in the trunk, and the Proboscis is articulated to 

 it, hence the variation of the angle to which it may be inclined. 



The Ocular tubercle is stout, sharply conical above the eyes, which are well 

 developed and four in number. 



The Abdomen is quite small and articulated to the trunk. 



The Palps are ten-jointed. The third joint is much longer than the fifth, which 

 reaches almost to the extremity of the proboscis. The fourth joint is very small, and 

 the seventh is slightly longer than the sixth ; the eighth is quite short, the two 

 terminals being twice its size and sub-equal. Towards the extremity of the fifth joint 

 very minute setae make their appearance, and on the rest of the appendage they are 

 scattered in more or less definite rows. 



Ovigers : These appendages arise close to the middle line behind the palps (fig. 3). 

 The first three joints are very small, the fourth and sixth long and sub-equal, the 

 sixth as a rule extending beyond the proboscis. The fifth joint is about half the 

 length of the sixth. The four terminal joints are sub-equal, and the claw has a 

 peculiar appearance, as if the inner margin had been bevelled ofi" at a very acute 



VOL. III. ^ 



