REPORT ON THE PYCNOGONIDA. 87 



Fhoxichilidium molhssimum, n. sp. (PI. XIII. figs. 6-9), 



Diagnosis. — Body robust, lateral processes not very widely separated. Mandibles 

 distinctly three-jointed, with curved, smooth, and not very long pincers. Ovigerous legs 

 ten-jointed, without claw (probably present in both sexes). Auxiliary claws (1). Palpi 

 represented by small rounded protuberances. Legs with silky hairs. 



Description. — 



Of this interesting deep-sea Pyenogonid, unfortunately only a single specimen 

 (much injured) was collected during the voyage of H.M.S. Challenger. There is not 

 a single complete leg; and of the incomplete ones, with their three joints, there are in 

 all only three present. However, this form is so highly characteristic that I think it 

 possible to give, even from this defective specimen, a description which will be recognised 

 by future investigators. 



The body is robust; like the proboscis, the lateral processes, and the first joints of the 

 legs, it is entirely smooth. The front of the cephalothoracic segment projects over 

 the base of the proboscis. This front part bears dorsally the blunt oculiferous tubercle, 

 with its rudimentary eyes, and quite anteriorly the large mandibles are inserted. These 

 run parallel to one another, and are distinctly three-jointed. The basal joint is -com- 

 paratively long, swollen at its base, and again at the extremity ; the second is about 

 two-thirds the length of the basal joint; the third joint is very short, and terminates in 

 a pair of smooth, strongly-curved pincers, which, when closed, have a wide interval 

 •between them. 



The proboscis is very stout, swollen a little in the middle, and also at the extremity ; 

 seen laterally, the swelling at the extremity appears rather stronger on the dorsal than 

 on the ventral side. The triangular mouth is quite closed by the labial plates-. Near 

 the base of the proboscis the cephalothoracic segment bears on both sides a small blunt 

 protuberance, which represents the palpus. 



The ovigerous legs are inserted ventrally. Seen from that side, the cephalothoracic 

 segment is distinctly divided into two segments, and the ovigerous legs originate from 

 the first of these two segments. They are inserted on small processes, which represent 

 the lateral processes of the ovigerous legs, and have ten joints. The first and third 

 joints are short; the second is about twice as long; the fourth is comparatively stout and 

 longer than the second; the fifth is as long as the second, and much more slender 

 than the fourth; the sixth is shorter than the fifth* slender, but swollen at the extremity. 

 The last four joints do not show any great difi"erences in' length; however, from the 



