1897.] : Zoology. 345 
like, and is provided with blunt pseudopodia. In color it is often yel- 
lowish-brown, its plasma of a vacuolar honey-combed appearance, and 
its endoplasm with a large number of granules. Its central nucleus is 
vesicular and has an alveolar structure. Beside it isa peculiar refrac- 
tive accessory body unlike anything found in other ameba. This, 
during the process of division, seems to divide before the nucleus. 
(2) An encysted stage, in which the vacuolar appearance disappears, 
the pseudopodia become retracted, and a cyst-membrane is formed. 
The sequence of division is (a) the accessory body, (b) the nucleus, 
(c) the plasma. 
(3) A flagellate stage that begins by the emergence from the cyst of 
oval swarm spores, each possessing two flagella, an ingestive aperture, 
two chromatophores, a nucleus, and, like the first stage, an accessory 
body. Leaving out of account this last body the organisms very closely 
resemble species of Cryptomonas. Sometime after emerging from the 
cyst the spores divide longitudinally, lose their chromatophores, and 
become ameeboid. 
Diplodal Sponge-Chambers.’—Prof. F. E. Sohults =o a re- 
examination of the matter, using as examples, Corticium n O. 
Sch., Chondrilla nucula O. Sch., and Ovoureila lobularis, jive his 
observations made on the adie chambers of the last form in 1877. 
The chambers have both an entrant and an exit aperture. 
The Asymetry of Spirorbis and the Phylogenetic Rela- 
tionships of the Species of the Genus.’—As a result of the 
examination of a large number of specimens of this genus derived from 
various parts of the world, and comprising a score of species, it has 
been found that these serpulids are entirely asymetrical. The form of 
the spiral is constant for a given species, and is either dextral or sines- 
tral. In the dextral species the operculum is always borne by the 
second right branchial, while in the sinestral forms it is borne on the 
left second branchial—thus, in all cases, on the concave side of the 
animal. 
The muscle-fibers are developed to the greatest extent on the concave 
side. 
The intestine and ovaries are crowded to the convex side. 
The uncini are most numerous and largest on the concave side. 
In the abdominal region there are, speaking generally, n rows of 
uncini on the right and n + p rows on the left side (p. = 2 
* Zool. Anz., XIX (1896), pp. 426-32. 
° M. Caulberg and Félix Mesnil. Comptes-Rendus, CXXIV (1897), pp. 48-50. 
