60 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Budding in Ccelentera.* * * § — Herr O. Seeliger has studied the formation 
of a hydranth on the main stem, and of a blastostyl on the secondary 
hydranth, of Eudendrium racemosum, and the budding of a medusoid on 
the blastostyl of the gonangium in Obelia gelatinosa. In every case both 
ectoderm and endoderm share in the formation of the bud. Thus he 
very thoroughly dissents from the conclusion of Albert Lang, that the 
bud of Hy droids ( Hydra in particular) is wholly ectodermic. Braem, 
working at Hydra and hydroids, has also controverted Lang. In the 
general part of his paper, Seeliger runs a tilt against the conception of a 
special Knospungs-Keimplasma, which appears to him gratuitous. 
It should be noted, however, that Lang I has answered Braem’s 
criticism of his work, and adheres to his conclusion that the hydroid bud 
is ectodermic. 
Porifera. 
Metamorphosis of Freshwater Sponge. J — Dr. B. Noldeke does not 
come to quite the same conclusions as his predecessors, Goette, Maas, or 
Delage. He finds that the larva of the freshwater Sponge consists of a 
flagellate ectoderm and an endoderm ; the attachment of the larva is 
dependent on the differentiation of the peripheral endodermal layer, but 
is independent of the further differentiation of the endoderm. After the 
attachment of the larva the ectoderm wanders into the internal mass, 
where its cells are eaten and digested by definite endoderm cells. The 
epidermis of Spongilla is of endodermal origin, but is formed out of the 
epidermal layer. The whole Sponge is to be credited to the larval endo- 
derm. The flagellate chambers have no connection with the larval 
endodermal cavity or the ectoderm; they are independent structures 
which may arise in the free larva. 
Dealing with the subject from the theoretical point of view, the 
author concludes that Sponges have a typical Gastrula with ecto- and 
endo-derm, which have the typical topographical relations to one another. 
The conversion of the germinal layers of the Sponges does not correspond 
to that which is known as the typical mode. The ectoderm, after the 
attachment of the larva, undergoes a process of degeneration, in con- 
sequence of which it takes no part in lorming the adult animal. After 
the Gastrula-stage is passed Sponges have no further genetic relations 
with any other of the Metazoa. 
In a postscript the author points out that Maas’ recent researches on 
the embryonic development and metamorphosis of the Cornacuspongise 
confirm the accuracy of his observations, but he refuses to accept 
Dr. Maas’ deductions. 
Protozoa. 
Infusorian living on Comatulid .§ — M. L. Cuenot recognizes in the 
Urceolariid Hemispeiropsis Comatulse of Konig the Infusorian which he 
described more than three years ago as Tricliodina antedonis. He now, 
* Zeitschr. f. wiss. Zoo]., lviii. (1894) pp. 152-88 (3 pis.), 
f Biol. Centralbl., xiv. (1894) pp. 682-7. 
i Zool. JB. (Abth. f. Anat.), viii. (1894) pp. 153-89 (2 pis.) 
§ Zool. Anzeig., xvii. (1894) p. 316. 
