172 Mr. E.. I. Pocock on the Qenus Urodacus. 



ous keel on the under surface of the hand ; on each side of 

 this keel is a series of setiferous punctures. 



Pectines not projecting so far as the distal margin of the 

 posterior coxte ; number of teeth 1 7. 



Colour piceous. 



Measurements in millimetres. — Cephalothorax, length 17, 

 width 16, as long as the first and second and one fourth of 

 the third caudal segments ; tail 63, i. e. about three and three 

 quarter times as long as cephalothorax ; length of fifth seg- 

 ment 15, width 4^, height 4 ; length of vesicle and aculeus 

 14. Length of humerus 12, of brachium 14, of hand-back 

 14, of movable finger 19, width of hand 11 1, height 9| ; 

 length ofpecten 9, of pectinal tooth 1|-. Total length 116. 



A single dried specimen (which, from the shortness of the 

 pectines and of the tail, I believe to be a female) from Port 

 Essington. 



This is a well-marked species, conspicuous for the smooth- 

 ness of its hands and cephalothorax and for its large size. 



Urodacus armatus, sp. n. (PI. VIII. figs. 3, 3 a.) 



CephalotJwrax with a shallow circular incision in the middle 

 of its anterior margin ; furnished throughout its length with 

 a cons})icuous median sulcus, which posteriorly dilates into an 

 equi laterally triangular depression. The posterior portions 

 of the right and left halves of the cleft ocular tubercle not 

 terminating behind the eyes, but continuous with the margins 

 of this triangular depression. The anterior third of the 

 cephalothorax above horizontal, not granular, but slightly 

 rugose; the posterior two thirds laterally depressed and 

 granular. Immediately beneath the central eyes is a smooth, 

 slightly depressed area. Eyes very slightly nearer the ante- 

 rior than the posterior margin of the cephalothorax. 



Abdominal tergites finely granular and marked with a 

 low^ median, longitudinal crest ; on each side of the crest in 

 the middle of the tergite is a faint impression, and in the 

 anterior portion of the tergite an abbreviated sulcus. The 

 granules, crest, and impressions are less conspicuous on the 

 anterior than upon the posterior tergites. The posterior 

 abdominal tergite furnished laterally with two granular keels. 



Abdominal sternites perfectly smooth, the anterior half of 

 each, the last excepted, being marked with two sulci, the last 

 furnished in its posterior half with two smooth keels. 



The four proximal caudal segments smooth ; the keels con- 

 spicuous and smooth, with the exception of the superior and 

 supcro'lateral keels, which are slightly granular ; the superior 



