ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
399 
Tunicata. 
Polymorphism of Buds in Colella.* — M. M. Caullery notes, in 
regard to this genus, the characteristic disposition of the four rows of 
tremata, the unisexuality of the corms, and the origin of the buds in a 
manner similar to what occurs in Distaplia. He dwells, however, upon 
the occurrence of two hinds of buds (a) without reserve-substances, and 
(6) with abundant stores in the ectodermic investment. The latter, 
being far from the head, are, by their position, slow of developing ; it 
is probable that they regenerate the colony when the head portion is 
amputated. It is also noteworthy that as the ectodermic part of the 
bud is wholly given over to storage, all the organs arise from the internal 
endodermic portion. 
INVEHTEBRATA. 
Blood-Corpuscles.f — Prof. P. Owsjannikow has made a study of the 
blood-corpuscles of the crayfish and the fresh-water mussel. He finds 
that the blood-corpuscles of the former remain for a long time unaltered 
under the influence of either low or high temperatures. Lower tem- 
perature prevents also the coagulation of the blood. The nucleated cells 
are only distinct from the spindle cells by their further development, the 
former being only young stages of the latter. Phagocytotie phenomena 
are only seen in the young forms, or, at least very rarely also in the 
intermediate forms. The blood-cells consist of nucleus and protoplasm. 
The former consists of one or two or, oftener, of several nuclear frag- 
ments, a fluid and a membrane. The protoplasm consists of a spongy 
body and a fluid, and contains nuclei, and a limiting layer, which in older 
cells appears as a true limiting membrane. After this membrane is 
formed phagocytosis is no more possible. In the blood-corpuscles of 
the mussel there are also to be seen cells in various stages of de- 
velopment. 
Healing next with the lymph-glands of the crayfish, the author finds 
that, in various organs, the connective tissue contains aggregations of 
cells which in size, staining capacity, and other peculiarities, are seen to 
be lymph-cells. He was led, therefore, to the conclusion that, in addi- 
tion to one larger lymph-gland, there are in the body of the crayfish a 
number of smaller glands. These may be some day detected by 
injections. 
Stinging Cells. f — Prof. M. Bedot describes as spirocysts the cnidse 
cochleatse which Gosse noted in Actinozoa. They are simpler than 
cnidoblasts, and quite different. The thread is very probably without 
a cavity ; it is quite smooth and without barbs or the like, and issues 
directly from the cell without evagination or attachment. In fact, 
spirocysts are more like trichocysts than cnidoblasts. 
Bedot goes on to note the occurrence of nematocysts in Eolididae and 
Pleurophyllidiidee. In Pleurophyllidia lineata L. he saw spirocysts 
beside the nematocysts. As to their alleged occurrence in the cuttle- 
* Comptes Rendus, cxxii. (1896) pp. 1066-9. 
f Bull. Acad. Imp. Sci. St. Petersburg, 1895, pp. 365-82 (1 pi.). 
X Revue Suisse Zool., iii. (1896) pp. 533-9 (1 pi.). 
