TffALIACEA. POLYZOA. 
Moll 109 
wards the embryonal sac disappears, and the embryo passes into the 
epithelial cavity of the uterus. Todaro comes to the conclusion that the 
development of Salpa is complicated by metamorphosis, and that the 
development of the first embryo or pro-embryo, and its relation to that 
of the following “ true ” embryos vary in different species ; the preceding 
observations are made chiefly on Salpa pinnata (Forsk.). Atti Acc. Rom. 
Trans, vi. pp. 309-315. 
W. K. Brooks maintains that the simple Salpce are females, and pro- 
duce the eggs, and that the aggregate are males, which carry with them 
the eggs produced by the preceding generation. Stud. Biol. Lab. Hopkins 
Univ. xi. No. 2 ; abstract in Arch. Z. exp£r. x. p. lxii., and Zool. Anz. 
1882, pp. 212-215. 
Appendiculartje. 
Metamerisation in the caudal muscles of Fritillaria ; E. R. Lankester 
{supra, in General Subject). 
POLYZOA. 
J. Barrois has published another paper on the embryogeny of the 
Polyzoa , urging chiefly the relations of the larva to the adult form ; he 
recapitulates and discusses more particularly the principal parts of the 
larva and its metamorphosis in the type of the Endoprocta ( Pedicellina ), 
and several types of the chief divisions of the Ectoprocta, as Lepralia , 
Dugula , Serialaria , Frondipora , and Discopora , coming to the conclusion 
that the different forms of larvae may be grouped and characterized as 
follows : — 
1. Endoprocta : Predominance of the ab-oral surface, vestibule at the 
maximum; intestine well formed. 
2. Chilostomata and Ctenostomata (sac reduced) : Predominance of the 
circlet ; pallial cavity ; intestine reduced to a mass of globules. 
3. Cyclostomata and Lophopoda (without sac) : Predominance of the 
oral surface ; pallial cavity in the maximum ; intestine all but 
disappeared. 
The metamorphosis in all of them begins with the immersion of the 
oral surface in the embryo, accompanied by an extension of the ab-oral 
surface, which spreads out so as to form the whole of the integument 
which will give origin to the definitive cell. The oral surface, entirely 
invaginated, divides into two completely different parts, one of which 
remains adherent to the base of the cell, while the second advances up- 
wards to connect itself with the special invagination of the ab oral sur- 
face (invagination of the hood in the Ectoprocta , labial thickening in the 
Endoprocta ), and constitute with it the future polypide. In the Endo- 
procta , this second part, or superior division of the vestibule, is greatly 
developed, and consists of the median portion of the oral surface, which 
bears the incubatory pouch, and to which the intestine is suspended ; it 
forms of itself almost the entire polypide, while the invagination of the 
ab-oral surface hardly gives origin to more than the aperture of the cell, 
lu the Ectoprocta , the upper part of the wall of the vestibule only con- 
