Vol. 52.] FROM BRITISH COLUMBIA. 225 



This species has many points of resemblance to lleuss's Prosopon 

 verrucosum, from which, however, it differs in the greater anterior 

 breadth of Reuss's specimen, and in the form of the rostrum and 

 arrangement of the furrows upon the gastric and cardiac regions. 

 Reuss's P. verrucosum should probably be placed in Bell's genus 

 Homolopsis. 



In Homolopsis Edwardsii, Bell, from the Gault of Folkestone, the 

 frontal border is broader and the carapace more quadrate than in 

 the North American form, which is pointed in front ; the anterior 

 half of the carapace in H. Edwardsii is more coarsely ornamented 

 with fewer and larger tubercles, and the arrangement of the lobes 

 differs considerably from that in H. RicJiardsoni. 



I would refer this specimen to Homolopsis, and dedicate the 

 species to the discoverer, Mr. James Richardson. 



The specimen is from the Museum of the Geological Survey of 

 Canada, Ottawa. 



Legion Oxystomata. 



Family Corystidse. 



Genus Pal^ocorystes, Bell. 



In this genus the carapace is longer than broad, flattish, becoming 

 narrower gradually towards the posterior border, rostrum short, 

 latero-anterior border dentated. Orbits moderately broad, with 

 two fissures. 



The carapace in all the species of this genus at present known is 

 similar to that of the masked crab, Corystes, now living on our 

 English coasts. 



3. Palceocorystes Harveyi, sp. nov. (Fig. 4, p. 226.) 



The genus Palceocorystes, to which I have referred two of the 

 specimens sent to me by Mr. "Whiteaves, is well represented in the 

 Gault, Green sand, Chalk, and Eocene. 



Thus we have : — 



Palceocorystes Broderipii, Mantell, sp. ; Gault, Folkestone. 



Stokesii, Mantell, sp. ; Gault and Greensand, Cambridge and 



Folkestone. 



Normanni, Bell ; Chalk Marl. Isle of Wight. 



MiiUeri, Bink ; Upper Chalk, Maestricht. 



Callianassarum, Fritsch ; Chalk, Bohemia. 



isericus, Fritsch ; Chalk, Bohemia. 



glabra, H. W. ; Lower Eocene, Portsmouth. 



Eucorystes Carteri, M'Coy ; Greensand, Cambridge. 



Both the specimens from Canada are imperfect. One of them 

 (No. 2) shows the anterior upper surface of the carapace, the other 

 (No. 3) the posterior upper surface. From these we are able to 

 make the following diagnosis : — 



Specific characters. Length of carapace 35 millim., from the 

 rostrum to the broken posterior border (to this we must probably 



