34 
versant with the fixed relations of osteological and dental characters, 
that the three corresponding parts of three Pterodactyles for the first 
time discovered, should be appropriated to three distinct species, I 
have no other alternative, in obedience to the indications of nature, 
than to adopt such determination *. 
2. DESCRIPTION OF TWO NEW GENERA AND SOME NEW SPECIES 
oF ScuTELLIDZ AND ECHINOLAMPIDZ IN THE COLLEC- 
TION OF THE Britisa Museum. By Jonn Epwarp Gray, 
Esa., F.R.S., P.B.S. ere. 
The collection of the British Museum is extremely rich in species 
of recent Echinoids, and fortunate in possessing long series of different 
ages of several of the species. 
Having been recently occupied in arranging and forming a cata- 
logue of these animals, I transmitted to the ‘Annals of Natural Hi- 
story’ for February a description of several genera and species of 
Spatangide. 
MM. Agassiz and Desor having recently published, in the Mono- 
graph of Echini and other papers on these animals, all the species of 
these two families then known to them, and as they had every facility 
for examining the British Museum specimens, the species now to be 
described are but few in number. 
Fam. 1. ScuTELLIDZ. 
Genus EcHINANTHUS. 
Among the species which have the base concave, of which LZ. ro- 
saceus may be considered the type, are to be added— 
1. EcninantTuus AUSTRALASIZ,. 
Vent beneath, at a little distance from the edge; back very convex 
* The same criticism or objection may be offered to the conclusions in the text, 
as the following one, which was called forth by my determinations of the species 
of Balenodon found in the red crag. ‘The specimens exhibited by Prof. Hens- 
low were only eleven in number ; so that, without allowing anything for the cir- 
cumstance of each whale having ¢wo tympanic bones, and the probability of some 
of the above being in pairs, we have the first twelve determinable cetaceous bones 
discovered in the red crag appropriated to no less than five species. I have no pre- 
tensions to call in question the decision of Prof. Owen upon osteological grounds, 
but I must own that I am disposed, upon the doctrine of chances, to consider it 
hardly probable that these determinations are accurate.’’—Searles V. Wood, Feb. 
16, 1844, London Geol. Journal, p. 35. The fifth species is a gratuitous addition 
to the four described by me, the determinate characters of which have been con- 
firmed by numerous additional discoveries. Mr. Wood should have remembered, 
before he attempted to discredit the determinations from anatomy, and to substi- 
tute the numerical test, that the second mammalian fossil from the oolite, although 
a lower jaw, like the first, was of a different species, and that of five subsequently 
discovered unequivocal mammalian remains from Stonesfield, al/ are parts of the 
lower jaw, whilst two of them demonstrate a third species. Very improbable this 
to him, on the doctrine of chances; but only showing, as Sir Charles Lyell has 
remarked, “ the fragmentary manner in which the memorials of an ancient terres- 
trial fauna are handed down to us.” 
