1887.] MICROSCOPICAL JOURNAL. 49 
neous and singly refractive ; in the reproductive they are distinctly differen- 
tiated or doubly refractive. The different phases are discussed at length, 
but the problems of length, transition, and conditions are still unsolved. 
Some notes on the reproduction of Acanthometridz are then added. 
IV. Systematic.—The Spherozoida are distinguished from the Collo- 
spherida chiefly in these points :—In the formation of the anisospores in S. 
the grouped arrangement of the nuclei persists till the spores begin to be 
formed, while in C. it is of a very short duration; in S. macro- and micro- 
spores are formed in the same individual; in C., however, in different indi- 
viduals; in S. true extra-capsular bodies are formed, but these have never 
been observed in C. On account of these developmental differences, there- 
fore, the two families are distinguished. Since it is impossible to summarize 
the systematic portion of the work, it must suffice to summarize the net 
results. : 
SPH #ROZOA. 
Fam. I. Sphzrozoida. 
Collozoum, Hkl.—Usually without skeleton, occasionally with isolated 
spicules. 
1. C. inerme, Miiller sp. 
Za etUkvun, i. Sp: 
3.-** pelagicum, Hkl. 
4. ** Hertwigii, n. sp. 
Spherozoum, Mey.—With siliceous spicules. 
5. Sph. punctatum, Huxl. sp. 
6. ‘* neapolitanum, Brandt. 
. ‘** acuferum, Mill. 
Soe) Elaeckeli,:n-,'sp. 
9. ‘* spinulosum, Miill. 
Fam. II. Collospherida. 
Myxosphera, n. g.—Without skeleton. 
to. Myx. cerulea, Hkl. sp. 
Collosphera, Miill.—With smooth latticed shell. 
11. CoH. Huxleyi, Mill. 
Acrosphera, Hkl.—Latticed shell with pointed spines. 
12. Ac. spinosa, Hkl. 
Spinosphera, Miill.—Latticed shell, in which the principal apertures 
are drawn out into tubes. 
13. Sp. tubulosa, Mill. 
Vas tenerai mn. Sp. 
MIROSCOPICAL TECHNIQUE. 
Reagents for clearing celloidin-imbedded sections for balsam mount- 
ing. By Ira yan Gieson, M. D., assistant at the laboratory of the 
Alumni Association of the College of Physicians and Surgeons, 
New York. 
The reagents used in clearing celloidin-imbedded sections for balsam mount- 
ing may be divided into two classes, depending upon their property of dissolv- 
ing or of not dissolving the celloidin from the section. The oils of the former 
class are useful in clearing compact sections in which the celloidin is used 
merely to give proper consistency for cutting. In such sections the ordinary 
oil of cloves is the most convenient. The latter class of oils ‘is desirable for 
