REVIEWS. 
293 
Such is Mr. Proctor’s ingenious theory. In the present condition of as- 
tronomical science it is impossible to pronounce definitely in its favour ; but 
it certainly fascinates us by its simplicity, and by the fact that it collates a 
number of otherwise heterogeneous facts; whilst it is certainly less of the 
haphazard and “dernier ressort” character than Mr. Lockyer’s “glare” 
notion. At all events, whatever be its merits, or that of any of the other 
original ideas with which the book abounds, it is clear that Mr. Proctor’s 
volume is a most attractive and instructive one, and one which should be 
carefully read by all intelligent persons who come under Mr. (now Dr.) 
Matthew Arnold’s category. 
PTERODACTYLES.* 
I T is not many years ago that the remarkable fossils of the Cambridge 
Greensand which Mr. Seeley has now so well described were a veritable 
terra incognita to the palaeontologist. Till the publication of the present 
excellent volume, it would have been difficult for the worker to obtain 
in any one treatise all the information he might have desired as to the affi- 
nities and the remains of the Cambridge Pterodactyles. But now, thanks' 
to the author's labours, we have in this treatise an elaborate account of all 
that relates to the palaeontological history of the Cambridge Greensand 
Ornithosauria. Mr. Seeley has gone elaborately into his subject, so that 
indeed his book may well be regarded as a handy monograph on ptero- 
dactyles generally. In his earlier chapters he gives a sketch of the organi- 
sation of these curious reptiles, and an account of the fossil remains on 
which the earlier descriptions of the group were founded. Next he states 
in outline the views taken of these affinities by Cuvier, Sdmmerring, Oken, 
Wagler, Goldfuss, Wagner, Quenstedt, Burmeister, and Yon Meyer. Then, 
without basing his own opinion on those which have been enunciated by 
previous writers, he proceeds to reason on the a priori method, and adopts 
the view that the pterodactyles were neither birds nor reptiles, but were a 
group between the two, and entitled to a place of equal rank with the class 
birds. The following epitome, nearly in the author’s words, gives a notion 
of his doctrine : — 
“ The Pterodactyles have a nervous system of the bird type ; they have a 
kind of brain which exists only in association with a four-celled heart and hot 
blood; they have a respiratory organisation which only exists among birds; 
with that respiratory apparatus is always associated a four-celled heart and 
hot blood, which it would necessarily produce ; and with that respiratory 
organisation is always associated a brain of the type that the Pterodactvle is 
found to possess. Therefore,” says Mr. Seeley, “ it is firmly indicated that 
the general plan of the most vital and important of the soft structures was 
similar to that of living birds.” He then goes on to say that these avian 
* “ Ornithosauria : an elementary study of the bones of Pterodactyles 
made from fossil remains found in the Cambridge Upper Greensand.” By 
Harry Govier Seeley, of St. John’s College, Cambridge. London: Beil 
& Daldy, 1870. 
