608 
ZOOLOGICAL LITERATURE. 
endocyst^^ or innermost granular layer of the maternal hydatid; 
but there are some points of dispute respecting their precise 
mode of origin. Leuckart gives a faithful resume of the views 
of Von Siebold, Kulil, Davaine, Huxley, and Naunyn (spelled 
Naumyn by our author), showing the various points in which he 
either diflPers or agrees with these several authors. 
Especially noteworthy also is our author's account of the 
anatomy and early stages of larval development of Bothrioce- 
phalus latus. He confirms the statements of Von Siebold and 
Schubart as to the ciliated character of the embryo, hut corrects 
Knoch in respect of several points connected both with the 
structure and phenomena exhibited by these minute organisms. 
Knoch had persuaded himself that he had succeeded in rearing 
young Bothriocephali in dogs from these ciliated embryos — that 
is to say, in a direct manner and without the intervention of 
any intermediate bearer. Leuckart successfully explains the 
causes which led Knoch to entertain so erroneous an opinion. 
Second only to the interest attaching itself to the Cestodes is 
that which obtains in the case of the Trematodes. Here our 
author is both scrupulously minute and accurate, and has added 
much to our previous knowledge of the minute anatomy and 
mode of development of these creatures.. He has not only 
shown that the eggs of Distoma hepaticum continue their deve- 
lopment after their expulsion from the maternal body, but has 
succeeded in tracing the development of the embryo both within 
and without the chorion. In the free swimming condition, the 
embryo of the common fluke is a finely ciliated larva, obconical, 
truncated anteriorly, furnished with a small central cephalic 
proboscis and a cruciform eye-spot. Its total length is about 
of an inch. In like manner he describes the free embryo 
oi Distoma lanceolatumi which is remarkably small, having a 
longitudinal diameter of about It is of a rounded form 
and ciliated only at the front part. 
The volume abounds throughout with novel and interesting 
facts, the greater part of which result from the author's own 
personal researches. Without detriment to any one, it may be 
truly affirmed that in the department of human helminthology 
Kudolf Leuckart has no equal. 
B. Separate Publications, 
Entozoa : an Introduction to the study of Helminthology, with 
reference, more particularly, to the Internal Parasites of 
Man. By T. Spencer Cobbold, M.D., E.R.S. London, 
1864. 8vo (608 pages, with 82 woodcuts and 21 plates). 
This elementary treatise is the first original work on Hel- 
minths which has issued from the English press. It is pro- 
fusely illustrated, some of the figures being coloured. It at- 
