122 



NEW YORK STATE MUSEUM 



B)- tabulating the differentials of these four species we shall indicate 

 the features in which the Grande Greve form is unlike the rest. 





p 1 e u r o p t y X 



stem m a t u s 



a n c h i p s 



d 1 b e li 



ceplialon 



short 



longer 



short 



short 



occipital ring 



no spine 



no spine 



spine 



no spine 



confluent papillae on 



conspicuous 



inconspicuous 



inconspicuous 



inconspicuous 



cheeks 











suture line on cheek 



flush 



flush 



depressed 



flush 



pygidium 











lateral ribs 



11-13 



9-10 



8-9 



8-9 



axial ribs 



'3-(i5) 



9-(ii) 



9-(i4) 



io-(i3) 



ribs 



deeply grooved, 



not grooved, 



not grooved, 



faintly grooved, 





rounded 



rounded 



rounded 



rounded 



caudal spine 



short, acute, 



broad, ol^tuse, 



slender, ex- 



broad, s m e - 





elevated ax- 



not elevated 



tended, up- 



w h a t ex- 





ially 



axially 



turned, not 

 elevated ax- 

 ially 



tended, up- 

 turned, blunt, 

 and not ele- 

 vated axially 



Sharing its principal structures with the other three and separated from 

 them by differentials which are of the same quality as those distinguishing 

 other members of the series, D. d o 1 b e 1 i represents a notably early 

 Devonic type of structure. 



Dimensions. Cephalon ; large examples attain an axial length of 

 40 mm and a width of 75 mm. Pygidium : An average example has a 

 length of 40 mm and a width of 60 mm. 



Localities. In the middle beds at Grande Greve and in the greenish 

 sandy beds 50 feet below the chert at Shiphead. 



Species name. A. H. Dolbel, of the William Fruing Co. Lt., the 

 leading fishing establishment on the Forillon. 



Dalmanites lowi nov. 



Plate 9, figures 6-8 



A very distinct type of structure is presented by a few pygidia which 

 are of considerable size, relatively quite short, broad at the top, with pleural 



