Prof. F. M'Coy on some new Cretaceous Crustacea. 117 



suture dividing it from the posterior portion strong. Chelce 

 very large, extending beyond the rostrum as far as from thence 

 to end of tail-fins, depressed, obtusely carinated at the outer 

 and inner edges, moderately convex in the middle ; right hand 

 much narrower than the left, semielliptical, its greatest width 

 (at base of moveable finger) 1 inch, equaling the length of 

 the carpus, or two-thirds the length from the base of moveable 

 finger to the carpal joint ; the external margin of the penulti- 

 mate finger gently arched, nearly smooth, flattened above and 

 below ; internal margin of hand and moveable finger straighter 

 than the external one, the former nearly smooth, the latter lobed 

 by five or six very large flattened tubercles ; cutting edges of 

 both fingers straight, set with very numerous, small, close, ob- 

 tuse tubercles ; length of the last finger about 2 inches 4 lines ; 

 length of penultimate joint or hand, from carapace to tip of 

 penultimate finger, about 4 inches 4 lines : left hand subtri- 

 gonal, length of carpus to tip of fingers 1 inch 1 line, width 

 at base of penultimate finger 1 inch 3 lines, but the margins, 

 which are nearly straight from the carpus, continue to diverge 

 at about the middle of the fingers, and are thence strongly 

 arched inwards towards each other; length of moveable finger 

 1 inch 9 lines, cutting edge of both fingers much arched, the 

 points being incurved, each set with one very large bluntly 

 conical tooth at about one-third its length from the apex, and 

 two large rounded teeth at about one-third the length from 

 the base ; the inner margin of the hand is lobed by five or 

 six large compressed tubercles, both hands covered with a 

 coarse granulation (averaging three granules in 2 lines), with 

 eight or ten scattered tubercles nearly a line in diameter ; car- 

 pus on each side trigonal, about 1 inch 3 lines long, having a 

 granulation like that of the hands, and six or eight irregularly 

 scattered tubercles on the upper surface, a little more or less 

 than a line in diameter. Length of tail-flaps 11 lines, entire 

 length of abdomen 3£ inches. 



This species is easily distinguished from the only other creta- 

 ceous species {H. longimana, Sow. sp.) by the much superior size, 

 and by the great width and flatness of the chelse. The beautifully 

 perfect specimen which I figure of this species, was collected by 

 S. M. Saxby, Esq. of Caius College, Cambridge, whose extensive 

 collection of Isle of Wight fossils is so well known through the 

 labours of Dr. Fitton and others. I have great pleasure in de- 

 dicating it to him. 



Very rare in the upper White rag beds of the Upper green- 

 sand of Bonchurch, Isle of Wight. 



Coll. Mr. Saxby. 



