Mr. E,. I. Pocock on the Genus Urodacus. 173 



keel posteriorly raised into a conspicuous sharp tooth ; upper 

 surface of fifth segment flat and smooth ; superior keels 

 granular, supero-lateral keel smooth and abbreviated, infero- 

 lateral keels granular and converging in front, inferior median 

 keel granular, space between the keels of the lower surface 

 granular ; vesicle finely granular beneath, smooth above, 

 marked with five faint sulci — one median, two lateral, two 

 inferior ; aculeus gently curved. 



Chela. — Upper surface of humerus bounded in front and 

 behind by a row of denticles and bearing a few smaller 

 tubercles ; anterior surface bounded above and below by a 

 row of denticles and furnished with two or three tubercles, 

 inferior surface proximally granular, posterior surface smooth ; 

 the inferior surface not separated from the posterior by a row 

 of tubercles. Anterior surface of hrachium bounded above 

 and below with a row of tubercles ; for the rest the segment 

 is smooth, furnished above, below, and behind with four faint 

 keels ; posterior portion of inferior surface bearing a row of 

 setiferous punctures. 



Hand strongly keeled, stout, faintly reticulated above, 

 sparsely and feebly granular on its anterior (inner) surface, 

 more strongly granular on its anterior-superior edge. Supe- 

 rior surface bearing a conspicuous keel and separated from 

 the posterior (outer) surface by a strong keel, which is con- 

 tinued on to the immovable finger ; posterior surface also 

 medianly keeled and separated from the inferior surface by 

 a strong keel, upon each side of which is a series of setiferous 

 punctures ; anterior surface bearing two granular keels, the 

 inferior of which separates this surface from the lower surface. 



Pectines long, projecting considerably beyond the distal 

 margin of the coxa3 of the posterior legs ; number of teeth 

 21-22. 



Colour ochraceous. 



Measurements in millimetres. — Cephalothorax, length 10, 

 width 9^, as long as the first and three fourths of the second 

 caudal segments ; tail 45, i. e. four and a half times as long 

 as cephalothorax ; length of fifth segment 10, width 4, height 

 3 ; length of vesicle and aculeus 9^ ; length of hand-back 7, 

 width of hand 7, height 5^, length of movable finger 8^ j 

 length of pecten 8, of pectinal tooth 1-^. Total length about 

 74. _ 



A single specimen (a male in the dried state) from Port 

 Lincoln, Australia. 



This species bears considerable resemblance to U. novce- 

 hollundice^ Peters, but may at once be distinguished from it 

 by the form of its superior caudal keels. 



