16 
GERVILL1A aviculoides. 
(Perna aviculoides. Min . Conch, tab. 66.) 
TAB. DXI. 
Spec. Char.* Obliquely ovate-lanceolate, curved ; 
both extremities pointed ; hinge line nearly 
half the length of the shell ; hinge teeth few, 
similarly disposed. Distinguished from G. per- 
noides of Mons. Deslonchamps above quoted, 
by its more pointed form. 
At the request of several friends, and for the purpose of 
further illustrating this species, we have given a second 
plate of it. It belongs to that division of the genus in 
which the lamellar teeth of the hinge are all nearly in the 
same direction. Fig. 1. is from a remarkably fine speci- 
men in the cabinet of our kind friend J.Vine, Esq. It 
exhibits the opposite valve to those figured on tab. 66. 
Fig. 2. is a portion of the hinge with two lamellae. Fig. 3. 
shows a front view of both valves, in which their differ- 
ence is seen, one having a shallow furrow along it, which 
the other wants. These three specimens are from the 
Shanklin Sand. Fig. 4. is a cast of the inside, picked up 
on Shotover Hill, Oxford ; it shows the muscular im- 
pression and several of the points of attachment of the 
mantle. Fig. 5. the cast of the hinge nearly perfect, taken 
out of one of the same masses that produced the Gervil- 
lia solenoides. Similar casts are met with in Parham 
Park, but not, I believe, accompanied with the G. sole- 
noides. They are mentioned by Mr.Mantell(p. 74. n. 17.). 
Mr. De la Beche has found the same species in the lowest 
strata of Green-sand near Lyme. Hence it should ap- 
pear that it is a constant attendant upon that formation. 
* This will supply the place of the one formerly given. 
