318 



A -1 



" The genus PaUjcocorystes, to which I have referred two of the specij 

 mens sent to lue by Mr. Whiteaves, is well represented in the Gault 

 Greensand, Chalk and Eocene. 



"Thus we have : — 



Pakeocorijstcs Broderipii, Mantell, sp. ; Gault, Fulkestone. 



Stokesii, INIantell, sp. ; Gault and Greensand, Cambridge and Folkestone. 



Normanni, Bell ; Chalk Marl, Lsle of Wight. 



Midleri, Bink ; Upper Chalk, Maestricht. 



CaUianassarum, Fritsch ; Chalk, Bohemia. 



isericus, Fritsch ; Chalk, Bohemia. 



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



Eucorysten Garteri, M'Coy ; Greensand, Cambridge. 



" Both the specimens from Canada are imperfect. One of them (No. 2, 

 fig. 17) 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 add 15 millim. 

 more, making the total length from the rostrum to the posterior border 

 of the carapace 50 millim.) ; greatest breadth ^10.. 17. 



across the hepatic region 37 millim. ^^^j^ 



" (No. 2 was collected by Mr. W. Harvey, 

 Comox lliver, Vancouver Island, 1892 ; No. 3 

 by Dr. C. F. Newcombe.) 



"Carapace smooth and gently convex in front, 

 and very finely and minutely granulated. La- 

 tero anterior border armed with four serrations 

 on each side, frontal border marked by one pro- 

 minent and one smaller tooth on either side of 

 the small bifid rostrum, while two fissures mark 

 the margin of each orbit. Under surface of 

 carapace not exposed. 



" The regions of the carapace are very indistinct ; two slightly divergent 

 raised lines about 5 millim. in length mark the frontal region just behind 

 the rostrum, and there is a faint ridge down the centre of the carapace. 

 A small tubercle on either side, behind the frontal region, marks the 

 epigastric lobe. A faint curved and bifurcating line separates the gastric 

 from the cardiac regions, while two slightly rugosr; and incised lines curve 

 outward and forward from the central cardiac region, marking the limits 

 of the branchial region on either side. 



" Of the several species of Palmocorystes known, the present form, which 

 I have ventured to call P. Harveyi after its discoverer, approaches most 

 nearly to P. Broderipii from the Gault of Folkestone, but is probably 



'7 



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