28 FOSSIL MALACOSTRACOUS CRUSTACEA. 



In Mr. Cunnington's collection is a specimen consisting of a tolerably entire carapace, 

 wanting, however, the rostrum and the anterior margin, and of three segments of the 

 abdomen ; there are also fragments of the anterior pair of legs, evidently belonging to the 

 same individual, consisting of the arm and wrist, both imperfect. These materials are 

 sufficient to indicate the genus, and to distinguish the species from all others. 



The carapace is nearly cylindrical and evenly rounded, excepting that the sides are 

 very slightly compressed. The whole surface is granulated, the anterior portion more 

 coarsely, and almost scabrous, and the prominent granulations are directed somewhat 

 forwards ; there are indications of two converging carinas passing to the rostrum, and of a 

 smaller one on each side, as in H. sulcirostris and H. Saxbyi, and there is a spine at the 

 base of the supra-orbitar process ; the carapace is divided through its whole length by a 

 thin, linear sulcus. The abdomen is cylindrical and granulated ; the epimeral plates 

 mucronate in the middle of the margin, the second very broad. The anterior legs are 

 somewhat unequal, but less so than in //. longimana and some other species. The wrist 

 is long, much compressed, and has four large tubercles at the distal margin. 



Length of the carapace 2*1 inches; height 1'2 inch ; measurement over the back, from 

 one lateral margin to the other, 2-7 inches. 



05s. This fine species from the Greensand of Wiltshire has the almost circular 

 carapace and abdomen which characterise the genus, the same even direction of the nuchal 

 furrow, and the same peculiar form of the lambdoid furrow. The granular surface of the 

 carapace, becoming almost scabrous at the anterior portion, and an obvious tendency to 

 carination at that part, are equally characteristic of this numerous and widely extended 

 genus, and are quite sufficient, notwithstanding the absence of the rostrum and of the 

 supra-orbitar spine in all the specimens observed, to justify the position I have assigned to 

 this species. It has hitherto only been found in the locality mentioned, and exists, I believe 

 exclusively in Mr. Cunnington's collection. 



Hoplop aria scabra, milti. Plate VII, figs. 3 — 7. 



Testa maxima, lata, regionis branchialis parte posteriore granulis magnis, distinctis, 

 elevatis scabra; parte anteriore ejusdem et regione gastrica tuberculatis. [Brachio 

 triquetro, carinis tuberculato-spinosis (?) .] 



Descr. The carapace is remarkably large, indicating an animal nearly twice the size 

 of the majority of the species of the genus. The gastric region and the anterior part 

 of the branchial are tuberculated, as is also the median line of the carapace ; in the latter 

 the tubercles are in two irregular rows, and almost spiniform ; the broad metabranchial lobe 

 is covered with large, regular granulations, which are sufficiently prominent to render the 



