DECAPOD CEUSTACEANS OF THE OXFORD CLAY. 547 



siderably in size and form. Length of carapace 30 millim. ; height 

 of carapace 15 ; length of chelae 30 ; width of propodite 14. 



Oxford Clay, St. Ives. 



Specimens exist in Mr. George's and my own collections, and 

 in the British, Woodwardian, and Oxford Museums. 



The St. Ives specimens are of larger size than those figured by 

 Meyer and Oppel, and the cephalothorax is relatively less elongated 

 in form ; it also differs in that the tubercles on the anterior moiety 

 are larger and more numerous. 



The Oxford Clay carapace figured by Etallon (Cr. Jur. pi. viii. 

 fig. 8d) represents the Huntingdonshire form much more nearly 

 than does that of Oppel from the Kellaways Rock. The latter 

 author in his description (Pal. Mitth. p. 29) does not mention the 

 occurrence of tubercles on the surface ; but by the courtesy of Prof, 

 von Zittel I have had the opportunity of examining the original 

 figured specimen, and have ascertained that tubercles do exist, 

 but are of relatively smaller size than on the St. Ives specimens. 

 Etallon mentions this character as existing in specimens which 

 have come under his observation. It seems not improbable that it 

 may prove to be desirable to regard the Huntingdonshire form as a 

 distinct species, by reason of the difference in the form of the 

 carapace and in the character of the tuberculation. If so, I would 

 suggest the specific name of JS. Etalloni in honour of the distin- 

 guished palaeontologist, who has contributed so largely to our know- 

 ledge of fossil Crustaceans. Specimens occur somewhat abundantly 

 at St. Ives. 



Ertma ventrosa, Meyer, sp. 



Klytia ventrosa, Meyer, Neue Gatt. foss. Krebse, tab. 4. fig. 29. 



Eryma ventrosa, Etallon, Notes sur les Cr. Jur. du Bass, du Jura. 



I have seen two specimens of this species, each of them showing 

 a nearly complete carapace, the characters of which correspond 

 with those given by Meyer and Etallon, and also with those of a 

 plaster cast of a specimen from Mailley, Haute Saone, for which I am 

 indebted to the courtesy of Prof, von Zittel. They are of somewhat 

 smaller size, and the carapace is not quite so long in proportion to 

 the height — 16 milhm. by 30 millim.; the Mailley form 20 millim. 

 by 40 millim. The tubercles also are more closely arranged in the 

 St. Ives specimens, about 10 in a quarter-inch on the metabranchial 

 region. In some portions of the carapace of one of the specimens 

 a crescentic depression occurs in front of each tubercle ; this is a 

 character which Etallon (Cr. Jur.) assigns to E. siihventrosa. 

 A chela of the second (or third ?) pair of limbs has the hand about 

 three times as long as wide, with straight, subequal fingers half 

 the length of the hand, each impressed by a series of rather large, 

 setigerous pits. 



Oxford Clay, St. Ives. 



Coll. Mr. George, Northampton. 



Two specimens examined. 



Etallon gives a full analysis of the characters of this species, 

 which appears to be a widely distributed form. 



