ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
355 
tentacles. The antero-raedian and postero-median chambers become 
hollowed out in cellular buds which depend from the endodorm. The 
posterior chamber and the septa which bound it are only just anterior in 
development to the directive chamber and septa. The succeeding septa 
are formed in pairs and in the form of folds of the endoderm, in the 
postero-median chamber. These folds first arise on the neural surface. 
The two septa of a pair do not arise simultaneously, but successively, 
the left one being always in advance. 
Each new pair of septa arises behind that just formed, with the 
exception of the directive septa which appear a short time after the septa 
of the second pair. No trace of longitudinal muscular fibres can be 
found in the directive or the other septa. On the other hand, a layer of 
ectodermal muscular fibrils appears early in the wall of the body. It 
follows from this account and the description of Kowalevsky, that the 
larvae of Boveri are not the larvae of a Cerianthid ; the conclusions to 
which he has come as to the phylogeny of the group depend, therefore, 
upon an error of interpretation. 
The development of Cerianthids differs ab initio from that of the 
Hexactinaria, though certain resemblances are to be seen between them ; 
we cannot suppose that the Cerianthidae, in the course of their develop- 
ment, pass through an Edwardsia- stage. Edwardsia has muscles in the 
septa which are wanting in Arachnactis. 
Protozoa. 
Notes on Ciliated Infusorians.* — M. Fabre-Domergue gives an 
account of Lagynus Isevis Quenn. It is extremely flexible and contractile, 
bending before obstacles and contracting suddenly at the least cause for 
alarm. It varies extremely in form, and the colour varies with the 
degree of repletion or emptiness of the individual. It often feeds on 
prey of enormous size, which it swallows after dilating its buccal orifice 
to a considerable size. It multiplies abundantly by division in a cyst ; 
this cyst is rounded and has a fine, structureless, and colourless envelope ; 
the contents are granular and opaque in consequence of the presence in 
the endoplasm of a large number of refractive granules. 
Frontonia marina sp. n. was found among putrefying Algge at Concar- 
neau. The trichocysts of living specimens appear like small, dark, 
highly refractive dots when seen from in front ; from the side they look 
like rods slightly swollen in their middle, and set almost perpendicularly 
to the surface of the endoderm. When treated with ammonia, after 
fixation with osmic acid, they increase considerably in all directions, 
and lose their characteristic refrangibility. When protruded the 
trichocysts form long filaments like those of Paramsecium aurelia. 
Fabrea salina.j — Under this name M. L. Henneguy describes a new 
Heterotrichous infusorian found at Croisic. It is from 0*45 mm. to 
0*13 mm. long, with a pyriform body, the anterior end of which is 
deeply excavated and carries the peristome. It is violet or greenish 
black in colour. The peristome is elongated and directed from left to 
right. It is remarkable for a well-defined pigment-spot which is found 
* Ann. de Microgr., iii. (1891) pp. 209-19 (1 pi.), 
f Op.cit., 1890, pp. 118-35 (1 pi.). 
