86 THE ROY^ SOCIETY OF CANADA 



the lower edge of the sub-cai'dinal area. The dorsal margin is regularly 

 convex from the beaks to within a short distance of the posteal ex- 

 tremity, where it joins the posteal margin. In the larger of the two 

 specimens the anteo-ventral part of the margin is more sharply rounded 

 and projects farther in advance of the beaks than in the smaller. 



Gervillia cf. newcombii (Whiteaves). 



(Plate II, Fig. 2) 



A cast of the interior of a Gervillia with none of the test, little of 

 the posterior, and none of the anterior alation remaining. The lateral 

 surfaces are characterized by a longitudinal ridge, on the dorsal side of 

 which they fall away in a doubly concave form to a thin plate extending 

 to the hinge line. On the ventral side the surfaces are convex, and meet 

 at a comparatively large angle along the ventral margin. A broadly 

 elliptical adductor scar is visible on the dorsal side of the ridge. The 

 ridge forms an angle of about 30° with the hinge line, and is straighter 

 than that shewn in Whiteaves' figure of G. newcombii, which has a sig- 

 moid curvature and makes an angle of over 40° with the hinge line.* 



MOLLUSCOIDEA. 



Brachiopoda. 



Terebratula grahamensis (sp. nov.) 



(Plate III, Figs. 6 a, b, c) 



The general outline is roughly quadrate. The length is 30 mm., 

 extreme width 28 mm., convexity 14 mm., of which 9+ mm. are 

 referable to the pedicle valve and 4+ mm. to the brachial. 

 From the prominent beak of the pedicle valve the posterior 

 margins diverge in concave curves to near the greatest width of the 

 shell, which lies rather more than a third of the length from the beak to- 

 wards the anterior margin. At this point the lateral margins curve 

 rather sharply toward the front forming shoulders, between which 

 the outline of the lateral and anterior edges sweeps round in a continuous 

 curve. The pedicle valve has a decidedly incurved beak which projects 

 4 or 5 mm posteriorly beyond that of the brachial valve, and a fairly 

 well-defined cardinal area extends on either side of the beak to about 

 half the distance from the apex to the greatest width of the shell, and 

 the part of the posterior margin of the pedicle valve bordering this 



*Mesozoic Fossils, Vol. I, Part IV, p. 297, Plate XXIX, 1. 



