260 Dr. K. C. Schneider on some 
examining the nettle-pad ( Nesselwulst’’?) in Carmarina 
hastata, | realized that the two thickenings of the epithelium 
correspond to one another. I was also at first inclined to 
recognize a supporting tissue in them, as the Hertwigs * and 
others have done; but the observation of the living animal 
taught me that we here have to deal with a centre for the 
formation of nematocysts. In point of fact the filaments 
(“ Senkfiden ”) in Forskalea and the tentacles in Carma- 
rina are supplied with enidoblasts by the pad. In Carma- 
rina the elements are not large, but in Forskalea, on the other 
hand, where the nettle-buds also contain capsules of very 
considerable size, the whole course of development could be 
traced with wonderful clearness in their young stages at the 
seat of formation. J must admit that this is not exactly a 
very easy task; nevertheless with regard to the series of 
consecutive stages, as I shall subsequently figure them, I can 
affirm with tolerable certainty that it corresponds to the actual 
course of development. In my paper on Hydra + I supposed 
the thread to arise by ingrowth of the protoplasm into the 
cavity of the capsule, and thereby took the opposite view to 
Nussbaum } and Jickeli§, who observed a formation of the 
thread outside the capsule. At the present time, when I too 
have been able to confirm the mode of formation described by 
the two authors, I have read with real satisfaction that 
Bedot ||, whose papers I unfortunately omitted to consult 
before, found a development of the threads of the nemato- 
cysts in Physalia and Velella which agrees with that which I 
described for Hydra. The question might easily be asked, 
Who is right, or isevery body right? I am inclined to think 
that in the case of Hydra I overlooked or misinterpreted 
something or other—I shall, however, investigate the point 
afresh—and that Bedot did the same; for it seems to me to 
be not very probable that important differences of this kind 
should occur in the course of the development of the enido- 
blasts in animals which are so closely allied. This conclusion 
is strengthened by the fact that I believe I am entitled to 
assume that the thread develops outside the capsule in the 
Actinians also, as represented by Adumsia Rondeletit (see 
* O. and R. Hertwig, loc. cit. 
+ K. C. Schneider, “‘ Histologie von Hydra &c.,” Arch, mikr. Anat. 
35 Bd. 
{ M. Nussbaum, “ Ueber die Theilbarkeit der lebendigen Materie: II. 
Hydra,” Arch, mikr. Anat. 29 Bd. 
§ C.F. Jickeli, “ Der Bau der Hydroidpolypen, L,” Morphol. Jahrb. 
Gegenbaur, 8 Bd. 
|| Bedot, ‘ Recherches sur les cellules urticantes,” Recueil zool. suisse, 
t. iv. 
