91 
Amculopecten ovatus, McCoy, from wliicli, however, it is easily distinguislied 
by the number of radiating ridges, which is much greater on the Carboniferous 
speeies than on this one. 
Horizon and Locality. — A single speeimen has been found at Kempsey 
in a reddish phtanite, associated with a fragment of another speeies of the 
same genus and Atrypa reticularis, Linnyeus. 
3. Aviculopecten M‘Leayi, L. G. de Koninck. 
PI. Ill, Pig. 11. 
Though I am acquainted with this species from a fragment of the left 
valve only, still this fragment is sufficient to allow me to assert, without the 
least hesitation, that it is different from all those that have been hitherto 
described. It is the anterior portion of the valve, provided with its ear, that 
is the best preserved ; the middle portion has been fractured, is indistinet, 
and the posterior portion has completely disaj^peared. 
The following are the eharaeters I have been able to ascertain, and 
whieh will serve to enable one to reeognise the species when better specimens 
may have been diseovered. 
The shape is probably suborbicular, perhaps a little o'^’^al and elongate. 
The left valve is rather deep and regularly arched outwards ; the surfaee is 
ornamented with twenty to thirty radiating, fairly thick, plain, rounded ridges 
of a diameter practically the same throughout the median portion of the valve ; 
the five or six ridges elosest to the anterior margin are less regular, a little 
thinner than the others, and some even are bifurcated ; all these ridges are 
traversed coneentrically by numerous fine imbricating lamellae, formed by the 
suecessive and slightly irregular growth of the shell. The ear is large and 
rounded anteriorly ; it is furnished with several ridges (five to six) radiating 
like those of the remainder of the surface, but crossed by stronger lamellae, 
thieker and parallel to the margin. 
Dimensions. — Length, about seven centimetres ; thickness of the left 
valve, six to seven millimetres. 
o 
