^^jSZ^al.DeTrff PROGBESS OF MICROSCOPICAL SCIENCE. 327 
Schultze's Archiv for 1866, Bd. ii. Heft 4. I have tried it in compari- 
son with Dr. Bastian's process, and find it at least equal, and, I may- 
say, permanent, as I have sections of the brain of conger, made more 
than a year ago, which now show every nerve-fibre and cell in great 
perfection. Its manipulation is extremely easy, the brain, or other 
structure, being, as usual, hardened in chromic acid ; the section is put 
for a short time in spirits of wine, and thence transferred to the creosote, 
which makes it transparent in a few minutes; it is then placed in 
Canada balsam. The balsam will mix easily with the creosote, or 
the solution in benzole may be employed. As Dr. Bastian did not 
mention this process in his paper above referred to, I presume that it 
is not generally known in England, which must be my apology for 
occupying your space with this communication." 
The Anatomy of the Bep'oductive System. — In a paper read in June 
last before the Koyal Academic of Vienna, Herr Gussenhauer described 
a new method he had devised for the microscopic study of these struc- 
tures. It consisted in making a series of vertical sections, and it did 
not elicit any new points in structure. It is chiefly of interest from 
the fact that the author uses oil of cloves in preserving his specimens, 
and finds it answer very well. * 
The Homologies of the Polyzoa. — Mr. Alpheus Hyatt's paper on 
this subject, which was read in August before the American Associa- 
tion, is thus summarized : — The Embryology of the Hypocrepian 
Polyzoa shows that Loxosoma is the lowest of all in the order, and 
together with Pedicellina form the lowest suborder of the group. The 
progress of the whole order of Polyzoa is from this permanently in- 
vaginated form through intermediate stages to Cristatella, in which, 
when the polypide is inserted, even the stomach is carried up beyond 
the orifice of the cell. Thus the progress of structure is from an 
animal in which all the organs are crowded into the anterior end, into 
the coenoecial system, and to one in which the coenoecial or repro- 
ductive, evaginatory or gastric, and the lophoric or neural systems 
are all distinct when the animal is exserted. The Polyzoon may be 
transformed into a Brachiopod by simply enlarging the coenoecial 
wall and carrying it over, enclosing the lopliophore and reversing the 
position of the arms. Thus both the Polyzoa and the Brachiopods 
may be defined as sacs, closed at the posterior end by disks surrounded 
by tentacles, and perforated by an edentulous mouth, from which hangs 
the alimentary canal in the antero-posterior axis of the sac. The 
whole plan of the MoUusca was stated to be that of a simple sac, and 
the term Saccata proposed as more appropriate than that of MoUusca. 
The objection that the whole animal kingdom may be said to be sac- 
like has been raised. The Eadiata are, it is true, radiated sacs, the 
Articulata ringed sacs, and the Vertebrata sacs divided by the verte- 
bral axis, but the Saccata are typically sacs. 
