1863. | On Dr. Gerard’s collection of Spiti fossils. 137 
25. AVICULA ECHINATA ? Sowerby. 
Some specimens of sandstone are full of the valves of an Avicuwla, 
which appears to be identical with this widely ranging Oolitic species. 
None of them are sufficiently perfect to enable me to identify them 
with certainty, but the form of the ornamented valve, and the sculp- 
turing, so closely resemble those of the type specimens, that there is 
at least great probability of their identity. If any thing, the Spiti 
specimens are somewhat more orbicular than those of Hurope, but 
they vary somewhat in form, unless I have confounded two distinct 
species ; a question, which the state of the specimens does not enable 
me to decide satisfactorily. 
26. MytTiILus MyTILOIDEA, n.s. Pl. IV. fig. 8. 
M. testa semiovata, elongata; anticé truncata, angulate planata, 
recta ; posticé rotundata ; concentricé striata, haud costata. 
Length 2 inches. 
Height 1 ,, 
This shell has precisely the form of the common Mytilus edulis. 
The umbo of the only specimen in the collection, is wanting. 
Sub-kingdom. ANNULOSA. 
Class). HECHINODERMATA. 
27. Saumnta? PI. IV. fig. 9. 
An internal cast of a depressed spheroidal Hehinid with narrow 
ambulacra, pores in simple pairs, broad interambulacra with five or 
six plates in each row, and a very large circular disc, the plates of 
which are not however distinguishable. As regards form it might be 
either a Cidaris or one of the Salenide, but the size of the disc is 
such that it can only be referred to the latter family. It seems 
improbable from its association with Oolitic forms that it should 
belong to the genus to which I have referred it provisionally (all the 
known Salenias being cretaceous), but the dise is much larger than 
any known species of the oolitic Acrosalenta. 
LIST OF ILLUSTRATIONS. 
Plate I. 
Figs. 1, 2 a—c, Phragmacone and guard of Belemnites sulcatus, 
Miller. 
» 9, 38@ Ammonites acucinctus, Strachey. 
