﻿JURASSIC AND TRIASSIC BRACHIOPODA. 



Ill 



In addition to the species described several undetermined valves of perhaps other 

 species of Thecidium have been found by Mr. C. Moore in the Inferior Oolite of Dundry, 

 Sup., PI. XIII, figs. 14, 15, of which we have given drawings in the hope that they 

 may, in time, be correctly identified. 



Examples of a Thecidium much resembling Th. triangular e have also been found 

 attached to the specimens of Wold, curvifrons from the Oolite Marl of Leckhampton and 

 Washbrook, near Cheltenham. Another undetermined form was also collected by Mr. 

 Walker in the Coralline Oolite series at Ayton Quarry, near Scarborough. 



Genus Argiope, Beslong champs. 



61. Argiope ? oolitica, Dav. Sup., PI. XI, figs. 16, 16a. 



Spec. char. — Shell minute, wider than long ; dorsal valve semicircular, of moderate 

 convexity. Surface ornamented with thirteen rounded ribs of which the central one is 

 somewhat the largest. Ribs divided by interspaces of almost equal width ; hinge-line 

 as wide as the greatest breadth of shell. Ventral valve slightly deeper than the opposite 

 one, beak nearly straight, area triangular, flat, moderately broad, with a largish foramen 

 in the middle. External surface ornamented, as in the opposite one, both valves being 

 crossed by equidistant concentric lines of growth. Length 1 line, breadth 1 \. 



Ods.—Of this small shell Mr. Moore has found but a single example, and as nothing 

 is known respecting its interior, it is provisionally referred to Argiope, to some forms of 

 which it bears resemblance. 



Genus Zellania, Moore. 



At p. 145 of the « American Journal of Conchology,' vol. vi, part 2, 1870, Mr. Dall 

 considers Zellania to be a synonym of the sub-genus Cistella of Gray. I have not, 

 however, seen the loop in any of the many specimens of Zellania collected by Mr. Moore, 

 and consequently cannot say whether it agrees with that of Cistella. Mr. Moore observes 

 that Zellania has a large and rounded foramen, which, like that possessed by Platidia, 

 encroaches on both valves. 



