REVIEWS. 
191 
the genera have been also obtained from the chalk of Europe, thus pointing 
to the synchronism, as generally understood, between the chalk-formations, 
of Kansas and England. Another largely developed American group 
are the reptiles referred by Professor Cope to his order Pythonomorpha ,. 
including the mososauroid forms and their allies, which according to him 
represent an order of reptiles distinct from any other, and present charac- 
ters which ally them to both serpents and lizards. This order of reptiles 
attained a predominant importance during the Niobrara epoch of the creta- 
ceous period, as is indicated by the great profusion of individual remains 
and specific forms. Although occurring in America, wherever the cretaceous 
formation appears, they are more numerously represented in Kansas than 
elsewhere. The seas of the American continent appeared to be the home of 
this order, while they were comparatively rare in those of Europe, for in 
the latter country only four species have been recognised. Geologists will 
be grateful to Professor Cope for this final but elaborate report on the verte- 
brate fauna of America, showing that the cretaceous ocean of the West, 
teeming with an abundant and vigorous life, was no less remarkable for its, 
fishes than for its reptiles. 
ANIMAL PARASITES.* 
fflHE elder Van Beneden has passed so completely out of our recollection 
-L that we had imagined the present work was written by his son, a dis- 
tinguished follower in his father’s footprints. It is so many years since the 
late Dr. Lankester introduced to our notice in one of the Ray Society’s 
volumes the researches of Van Beneden and Kiichenmeister, that we had 
imagined that the Belgian professor had “gone the way of all flesh.” We 
are delighted that our ideas were mistaken ones, and that the first ex- 
perimenter on the subject of the Entozoa, and the demonstrator of the 
fact that the cysticercus of pig becomes converted into the tcenia solium or 
common tape-worm of man, has now written a book on the subject of animal 
parasites. There are very few outside the scientific world who have any 
idea of the vastness of the subject of animal entozoa. There is, in point of 
fact, no animal which has not got its parasite. Some, indeed, have many. So 
that it is not at all an erroneous statement, that animal parasites are the 
most numerous group of beings in existence. It is clear therefore that 
M. Van Beneden has had a very wide field before him from which to pre- 
pare the book now under notice. Indeed, we should have thought that it 
would have been too vast a subject for anyone to attempt the treatment of 
in a single volume like that before us. However, there are two modes of 
dealing with the subject, the scientific and the popular ; in the one of course 
the writer must treat at length, fully and completely, with each animal under 
discussion ; in the other he can pass in a sketchy manner along the field of his 
discourse, and can touch lightly on the more complex subjects, or enlarge 
* “Animal Parasites and Messmates.” By P. J. Van Beneden, Professor- 
of the University of Louvain, Correspondent of the Institute of France.. 
With 83 Illustrations. London : King & Co. 1876. 
