tiew Drachi/urons Cruslaeean. 530 



especially iiiterestiii*;; fr<im l)otli a inorpliolo^rical and cvolii- 

 lionaiy standpoint. 



Carcineretes * looolncotti, gen. et sp. ii. 



Diagnosis. — Carapace flattened, rectangular, very slightly 

 broader than long ; the protogastric lobes are the only ones 

 at all ])rominent, and are crossed by a transverse ridge — the 

 epigastric line; the frontal region is divided into throe lobes, 

 from which it is sharply deflected inwards and downwards to 

 form a shovel-like extension. Orbital region, on either side 

 of the front, wide, thrown into three lobes or teeth, de- 

 creasing in width towards the outer orbital angle, which is 

 produced into a prominent tooth, below the base of which the 

 orbit is deeply sunk. Chelipeds rather massive, with the 

 major chela developed on either the right or left. Last pair 

 of ambulatory legs with the propodus and dactylus flattened 

 and broadened to serve as a swimming organ as in the 

 Portunids. 



Occurrence. — Dr. Woolacott has supplied tlie following 

 notes regarding the horizon, locality, and associated species : — 



Upper Cretaceous (Turonian ?). From grey calcareous 

 shale in the bed of the Rio Minho a little to the west of 

 Trout Hall, Chapelton, Jamaica. The shale is several feet 

 thick, and one band of it, about 3 feet in thickness, is crowded 

 with Rudista>, forming a Rudist-bank. The crab-remains 

 were obtained from this bank. 



Ti»e crab-remains were associated with Rudistse, corals, 

 massive Actreonellid gastropods, and Ostrea-WX^Q bivalves, 

 the fauna being fairly rich and varied. Among the specimens 

 collected by Dr. Woolacott from the Cretaceous limestones of 

 Jamaica, Dr. Trechmann has determined the following : — 



Radioliles cancellatus, Whitfield f. 

 Radiolites cf. macroplicafus, Whitfield. 

 Caprina cf . jamaicensis, Whitfield, 



He states regarding the Rudist?e collected that " thoy 

 include several apjjarently undescribed forms, among them 

 being Radioliles both single and growing in clusters. 

 Among the former are forms having the general shape of 

 R. smivogesi of the European Cretaceous.^' The species 



* K-«pK(i'ns = crab ; 6p6r;;s= rower. 



t " Uescription of Species of Rudistoe from tlie Cretaceous Rocks of 

 Jamaica," Bull. Amer. Mus. Nat. Hist. vol. ix., July 1897, pi. xiii, 

 tigs. 3-7. 



36* 



