ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
311 
Gonads of Taenia polymorpha.* * * § — Herr K. Wolfflmgel finds that 
in this tapeworm the testes, vas deferens , and cirrus-apparatus, are paired, 
the last-named being peripheral ; that the female organs and uterus arc 
simple ; that the vagina is blind ; and that the cirrus perforates the 
cuticle, penetrating into the parenchyma. These peculiarities will pro- 
bably necessitate the establishment of a new genus. 
Helminthological Notes, f — Hi*. A. Mueller has notes on 24 parasitic 
worms, — including Ancyracanthus bihamatus sp. n. from the stomach 
of Sterna risoria, JEchinostoma tabulatum sp. n. from the intestine of 
Numenius arquatus, and Tsenia triangularis sp. n. from the intestine 
of Scolopax galinula. 
Echinoderma. 
Fertilisation and Cleavage of Echinoid 0vum4 — The late Prof. 
B. von Erlanger had made this the subject of one of his last researches. 
Both directive spindles have centrosomes, but the pole body of the inner 
pole of the second directive spindle disappears. The pole-bodies of 
the first directive spindle originate by the division of the middle portion 
of the spermatozoon ; and they divide again shortly before the formation 
of the daughter nuclei. The centroplasms or spheres are not, as Boveri 
alleged, much swollen central corpuscles. After the formation of the 
equatorial plate, the central corpuscles lie within the aggregate of 
vesicles, which occupy the central portion of the centroplasm. In 
regard to the mechanism of mitosis, the author argues against Heiden- 
hain’s theory of centered radii. 
Mediterranean Species of Synapta.§ — Prof. H. Ludwig discusses 
the different forms found at Naples and elsewhere in the Mediterranean. 
There are four securely established species, — Synapta iiihserens 0. F. 
Miiller, S. macranhjra sp. n., S. digitata Montagu, and S. Thomsoni 
Hcrapath. 
Growth-Changes in Integumentary Skeleton of Holothnrians.||— 
Herr Hjalmar Ostergren recalls the old observations of Baur (1864), that 
the young of Synapta inhserens and S. digitata differ from the adults as 
to their calcareous bodies. Semper, Herouard. Ludwig, Mitsukuri, and 
the author, have made similar observations. The present communication 
makes it probable that the organism distinguished as Holotlmria aphanes 
is the young stage of H. impatiens Forsk. 
Ccelentera. 
Experiments on Hydra. — Herr H. Peebles shows that there are 
limits to the regenerative powers of Hydra. The smallest parts of H. 
viridis which regenerate a hypostome and a tentacle measure 1/6 mm. in 
diameter. Tentacles do not grow into polyps, even if united in groups ; 
but if an excised tentacle has with it a small fragment of hypostome, 
it can regenerate a perfect hypostome and several tentacles. Similarly, 
a complete polyp may be regenerated from tentacles plus a portion of 
* Zool. Anzeig., xxi. (1898) pp. 211-3. 
t Arch. Naturges., lxiii. (1897) pp. 1-26 (3 pis.). 
X Biol. Centralbl., xviii. (1898) pp. 1-11 (12 figs.). 
§ Zool. Anzeig., xxi. (1898) pp. 1-9. || Tom. cit., pp. 233-7 (I figs.). 
1 Arch. Entwickmech., v. (I 89 ?) pp. 794-819 (34 figs.). 
