BIVALVIA. 89 
valves. Examples of this are supplied by the large Liassic Homomya ventricosa, Ag., 
by Homomya Vezelayi, D’Arch., and by Homomya crassiuscula, Mor. and Lyc. The 
hinge of the latter shell exhibits its perfect identity with that of Pholadomya. It is 
therefore evident that Homomya cannot claim a generic separation ; but that, viewed as a 
subgenus or section of Pholadomya, the name may conveniently be retained. Myacites 
Vezelayi, page 111, and Myacites crassiusculus, page 112, should therefore also be removed 
to Homomya. 
Homomya crassiuscuLa, Mor. and Lyc. Tab. XLIII, figs. 5, 5 a. 
A small example from the Great (?) Oolite of Lincolnshire was figured, Part II, 
Tab. XI, fig. 3. As the species occurs of full dimensions in the Cornbrash of Scarborough, 
a specimen, with the test preserved, is here given. 
