88 
PHOLADOMYA acuticostata. 
TAB. DXLYI. —Jigs. 1 & 2. 
Spec. Char. Oval-elongated ; with four or five 
large keel-shaped ribs upon * the very short 
anterior side,, and many gradually lessening 
ones over the middle of the shell. 
W ell distinguished even when much broken, by the 
large sharp ribs upon the anterior extremity. It is the 
smallest species we know of, the nearest like it is 
P. angustata, t. 327 . 
Brought from Brora by our valued and much-to-be- 
lamented friend, John Farey, sen. Esq. along with the 
last species. It occurs in the stratum immediately upon 
the coal. 
Fig. 2 . is from an impression in the limestone slate of 
Stonesfield, and seems to belong to the same species. 
PHOLADOMYA mqualis. 
TAB. DXLVI .—Jig. 3. 
Spec. Char. Oval, straight ; with six or eight 
equal slightly elevated ridges over the middle. 
Tiie two sides of this species are more nearly equal 
than those of others ; both are very obtuse. 
Found near Weymouth in clay replete with oolitic 
grains ; the shell is preserved stained by iron. 
