1866.] WOODWARD ERYON. 497 



for the extreme length of the forearms of the latter and the more 

 oval form of its carapace. 



3. Eryon crassichelis, spec. nov. PI. XXY. %. 2. 



I have had the opportunity of examining two specimens repre- 

 senting this species, — one a detached and folded carapace, exhibiting 

 the upper surface ; the other an almost entire example exhibiting 

 the under surface — a position in which at least nine-tenths of the 

 specimens occur, not only in our own Lias, but in the Lithographic 

 Stone of Solenhofen. 



The separate carapace (obtained by Mr. E. C. H. Day, F.G.S., 

 and now in the British Museum) is one-third broader than long, 

 and is altogether more rounded in form than E. Barrovensis or 

 E. antiquus. 



The branchial margin has along its border a row of strong spines, 

 which gradually decrease in size towards the frontal portion of the 

 carapace, where they entirely disappear. 



The indentations along the lateral margins of the carapace are 

 less deep, and the lobes formed thereby have not the pointed cha- 

 racter seen in E. Barrovensis and other species. The orbital fossae 

 are rounder, and have one spine on their exterior border ; the rostral 

 notch is but slightly indented. 



Between the orbital fossae and the nuchal furrow there is seen 

 upon the margin of Mr. Day's specimen a prominent round body, 

 which, from its form, is most probably the eye somewhat displaced ; 

 but in E. arctiformis they are placed outside the outer antennae. 



The surface of the carapace is uniformly and finely punctated, 

 and has the three ridges seen in Eryon Barrovensis ; but they are 

 not tuberculated, save at the posterior margin, where one tubercle is 

 placed at the base of each of the lateral ridges. 



A striking distinction marks this species, in the shortness and 

 thickness of the hands (as seen in an almost entire example from the 

 collection of Captain Hussey of Lyme Regis). The fixed and move- 

 able digits are less equal, broader, and more curved than in the other 

 English species. 



The four following pairs of limbs are only imperfectly preserved ; 

 nor does the underside of the abdomen yield much detail. 



The seventh segment (or telson) is perhaps more pointed, and the 

 caudal plates less round, than in E. Barrove7isis. 



The only species with which I am acquainted that is furnished 

 with hands like E. crasslchelis is the E. Escheri*, Oppel (also from 

 the Lower Lias) ; but the specimen is one-half the size and too 

 imperfect for comparison, save in the chelae. The specimen figured 

 by Oppel is from Miilligen, near Baden. 



Dimensions. — Carapace (detached) : length 2 inches 1 line ; breadth 

 3 inches (measured across the branchial region) ; breadth of frontal 

 portion of carapace 16 lines. 



Nearly entire specimen (Captain Hussey's collection) : —Greatest 

 length of animal 3 inches 6 lines ; greatest breadth of carapace 1 



* See Oppel, op. cit. t. 1. fig. 1, p. 10. 



