312 PROGRESS OF MICROSCOPICAL SCIENCE. 
I iVIonthly MiCTOsconioal 
L Journal, May 1, 1869. 
pellier. The author has gone tolerably minutely into the history 
of the development of this planarian, and has recorded the different 
phases in a large quarto lithographic plate. From his researches he 
concludes that it is doubtful whether there is such a thing as meta- 
morphoses among Planarise. Hence he remarks that the singular 
infusoria described by Joh Miiller and Claparede as the larvae of 
Planarians can hardly have any relation to this group at all. 
PKOGEESS OF MICROSCOPICAL SCIENCE. 
The Germinal Vesicle in the Egg. — In our last Number we gave a 
translation of M. Gerbe's important paper on the eggs of the Sacculin^e. 
Since the publication of that note M. Balbiani has stated that he 
himself, long ago, pointed out the existence of two vesicles in the 
ovum of various animals, and he objects to M. Gerbe taking the credit 
of that discovery to himself. In reply, M. Gerbe disclaims any idea 
of claiming that part of the discovery as his own. He says, " What I 
wish to establish is that in the ovule of the Sacculinae, as in all species 
vvliose ovum has a cicatricule, the vesicle which has for so long a 
period been known as the Germinal vesicle, is really that around which 
are grouped the materials destined for the development of the embryo, 
and which consequently should preserve the name that the first ob- 
servers gave to it. I also intended to establish that the second vesicle, 
that around which I have seen the nutrient matter develop itself, 
that is to say, the analogue of the yelk in birds, can have no other 
function than to accumulate this element." He contends that both of 
these propositions are correct, inasmuch as they are not based on pre- 
conceived ideas, but on careful examination of ova from their origin to 
their " maturation." — Gomjptes Itendus, March 15th. 
The Structure and Development of the Spermatozoa in Fishes have 
been studied by M. Owsiannikoff, who has presented a memoir on this 
subject to the Imperial Academy of St. Petersburg. The spermatozoa 
are far more complex in structure than is generally supposed by those 
who follow Kolliker's account. The author investigates the zoosperms 
of the Salmo salar, S. fario, Coregonus, and some forms of perch. The 
seminal glands have in their interior the structure of compound glands. 
They are formed of connective tissue, blood-vessels, nerves, epithelium, 
and spermatozoa ; and, as in other glands, the principal element is the 
epithelium. The epithelium cells, which have the ordinary cylindrical 
form, are placed in two rows, and are not separated from the rest of 
the tissues by any particular membrane. All of these possess a large 
white nucleus, which distinctly encloses a central corpuscle and pro- 
toplasm. The process of division of the cells is known. Cells may 
be seen which have acquired a considerable development, and which 
enclose from ten to fifteen secondary cells without losing their form. 
