88 QUARTERLY CHRONICLE OF MICROSCOPICAL SCIENUE. 
egg-follicle), nor do the testa-cells become the cells of the 
test, but the test is a cuticular formation derived from the true 
epidermis which lies below it, and which can always be de- 
tected in the adult. Into this gelatinous cuticula cells from 
the epidermis wander (not in Appendicularia and Doliolum), 
and form there a structure having a resemblance to stellate 
connective tissue. It is these cells which give rise to the 
various cells characteristic of the test in different genera. 
Further, villi from the body wall covered with true epidermis, 
and more deeply lined by true connective tissue, and con- 
tinuous with the hemolymph cavity of the Ascidian, may 
also push their way into this remarkable tegumentary excre- 
tion, and there give rise to branching ‘“ blood - vessels,” 
which have no inner (mesoblastic) epithelium. Hertwig has 
obtained the cellulose reaction from the deeper tissues of 
some Ascidians (Cynthia), such as muscular tissue and wall of 
the intestinal canal. . Semper, only too clearly influenced by 
the same unfriendly disposition towards the Jena School as 
he evinces in a paper (noticed below) on the segmental organ 
of sharks, whilst he is obliged to confirm Hartwig’s observa- 
tions, sneers at him as a young observer, and proceeds to an 
elaborate attack upon his use of the term “ Bindesubstanz,” 
which has only the emptiest verbal importance. Semper sides 
with Metschnikoff and Kupffer against Kowalewsky, as to the 
origin of the testa-cells. He holds that they proceed from 
the yelk, and compares them to the Richtungsblaschen of 
Mollusca. (The Reporter must remark that it is certain 
in the cases of several Mollusca that the Richtungsblaschen 
are the escaped germinal vesicle. Further, he would draw 
attention to the accumulation of epidermic cells often seen 
on the surface of Fritillaria furcata, corresponding to the 
mantle-cuticle of other Tunicates with its in-wandered cells). 
Vertebrata.— General Treatises —‘ Embryology of Verte- 
brates,’ by Foster and Balfour, is published by Macmillan. 
The present volume is the first of three, and deals with the 
development of the chick in great detail. ‘Two succeeding 
volumes are contemplated to treat of the other Vertebrata in 
a comparative manner, and of the Invertebrata—an amount 
of space which the authors will find quite inadequate if they 
deal with the subject as fully and clearly as they have in the 
present volume. The points of critical interest in the pre- 
sent treatise have already appeared in the pages of this 
Journal (1873), as well as many of the drawings, which are 
transferred to its pages in the form of woodcuts. A great 
merit of the book is that it takes up the embryology of the 
Chick in such a way that the University student can with its 
