PYCNOGONIDA. 49 



distinguished by the fact that in that species the abdomen is directed almost 

 vertically upwards, and is situated so far forward that the posterior trunk segment 

 passes over its base, a feature of, possibly, some morphological importance. 



Lbionymphon spinosum. 



(Plate VIL, fig. 2.) 

 Specific characters : — 



Body stoutly built, with the transverse ridges not very strongly developed, but with a very 

 prominent spur in the mid-dorsal line. The lateral processes are rather widely separated, and bear 

 distally two stout recurved spurs ; smaller ones exist on the first coxae. 



Proboscis short, not half the length of the trunk. 



Palps 9-jointed ; of the five terminals the seventh and ninth are a little longer than the others. 



Oviger lO-jointed, special spines not denticulate. 



The entire animal is heavily built, and covered with fine but short setae. The 

 lateral processes are rather widely separated, the intervals increasing posteriorly, two 

 pairs of processes are directed more or less forward, the other two pairs backward. 

 Each process bears dorsally at its distal extremity a pair of prominent recurved 

 tubercular processes ; these are also distinct, though less prominent, on the first coxse. 

 The body is crossed transversely by three ridges, but these do not extend on to the 

 lateral processes as much as in the allied species. These ridges stand erect, but they 

 are bevelled from behind in the middle line so as to form an acute point of some 

 considerable elevation, and this gives them the appearance of being arched forward. 



The Cephalon is not very much expanded, and almost fills the interval between the 

 first pair of lateral processes ; in front it bears a pair of tubercular processes directed 

 outwards, one at the base of each of the chelifori. 



The Ocular tubercle is just behind the centre of the cephalon and is very stout, taller 

 than any of the transverse ridges, and terminates in a cone above four well-developed eyes. 



The Abdomen is not separated from the body by an articulation ; it is of normal 

 proportions, elongate, ovate and directed slightly upwards. 



The entire body is covered with short, fine setae, but they appear to be deficient 

 between the ridges, and to some extent on the cephalon. Ventrally the transverse 

 ridges are rounded, and the median spur much less prominent than dorsally ; the setae 

 also are deficient. The length of the body is 13 mm., and its extreme width is 8 mm. 



The Proboscis is short and stout, being barely 5 mm in length, cylindrical, slightly 

 swollen in the middle, and movably articulated to the body. 



The Chelifori are rudimentary, they lie close together above the proboscis and are 

 more than half its length. The scape is half the length of the proboscis, very slightly 

 enlarged distally and clothed with short setae ; the chelae are only knobs, also setose, 

 and with but vestiges of the fingers. 



The Palps rise laterally below the chelifori and comprise nine joints (fig. 2a). The 

 first joint is short and stout, the proportions of the various joints being : 1 "5 ; 4 : 1 : 3'5 : 

 1 : 1 : 1'3 : 1 : 1"5. The entire appendage is covered with fine setae which become numerous 

 on the fourth joint ; on the four following joints they form a dense patch covering the 



s 2 



