67 



tenths in. breadth or thickness. A large left valve, from Durham, with 

 the test preserved, is seven inches and seven-tenths in length and its 

 maximum height is four inches and eight-tenths. 



Megalomus compeessus, Nicholson and Hinde. 



Megcdomu^s compressus, 'Nicholson andHinde. 1875. Rep. Pal. Prov. Ont., pp.68 



and 69, figs. 40, a-b. 

 " " Whiteaves 1884. This volume, pt. 1. pp. 10-12, 



figs. 1 and 2. , j 



This shell is found, but much less frequently, at the same localities as 

 the preceding species, of which it may be only a variety. 



GoNioPHOEA CBASSA, Whiteaves. 



Goniophora crassa, Whiteaves. 1884. This volume, pt. 1, p. 9, pi. 9, figs. 3, 3, a-c. 



Hespeler, T. C. Weston, 1867 • an imperfect cast of the interior of 

 both valves and a similar but nearly perfect cast of a right valve. Dur- 

 ham, J. Townsend, 1874-82 : several specimens, most of which are single 

 valves, with the test preserved. 



CONOCAEDIUM. 



Numerous specimens of a small and probably undesoribed species of 

 this genus were collected at Durham by Mr. Townsend in 1874-82, but 

 none of them are sufficiently perfect or well preserved to be described 

 with any reasonable degree of accuracy. They are either mere casts of 

 the interior of the closed valves, or fragments of moulds of the exterior of 

 the shell. 



Anodontopsis concinna, Whiteaves. 



Anodontopsis concinna, Whiteaves. 1884. This volu(ne, pt. 1, p. 12, pi. 2, fig. 4, 



and pi. 7, figs. 4 and 4 a. 



Gait, T. C. Weston, 1867 : a cast of the interior of a right valve : 

 Durham, J. Townsend ; a similar cast of both valves. 



Ilionia Canadensis, Billings. 



nionia Canadensis, Billings 1875. Can. Nat. and Geol., N. Ser., vol. VIII., p. 



301. 

 W'hiteaves. .1884. This volume, pt. 1, p. 13, fig. 3. 



Hespeler, T. C. Weston, 1867 ; five badly preserved casts of the interior 

 of as many closed valves : Elora, D. Boyle ; a similar specimen. 



