Martin, A Note on the Occurrence of Nematocysts and Similar Structures etc. 253 



im Korper stecken bleiben (z. B. Lionotus), wahrend sie bei anderen 

 ganz ausgestofien werden. Man hat diese Bildungen als Angriffs- 

 und Schutzwaffen gedeutet; doch 1st diese Deutung unsicher, und 

 es ist moglich, dass die Ausstofiung nur bei starken Reizen infolge 

 von Quellungserscheinungen erfolgt." 



The history of the earlier observations of these structures has 

 been given by Butschli in his account of the Protozoa in Bronn's 

 Tierreich, p. 1459. From this it would appear that the discharge 

 of these structures was first observed by Allmann in 1855. He 

 compared them to the Nematocysts of Coelenterates, but this view 

 seems now entirely discarded. For example, Minchin in his introduc- 

 tion to the Study of Protozoa. 1912, p. 447, states - "Nor does 

 there seem to be any ground for comparing it (the Trichocyst) to 

 a Coelenterate Nematocyst or to a polar capsule of a Cnidosporidian 

 spore". 



More modern views on the structure and mechanism of Tricho- 

 cysts can be found in the works of Schuberg and Khainsky. 



In my paper on "Some Observations on Acinetaria, Part 3, 

 The Dimorphism of Ophryodendron", Q. J. M. S., Vol. 53, Part 3, 

 May 1909, I have already had occasion to refer to two cases of 

 the presence of Cleptocnidae in the Ciliates in Kentrona and Holo- 

 phrya oblonga. 



The Kentrona in question were found crawling on rather moribund 

 hydra, and were found to contain undischarged Nematocysts of the 

 hydra in fair numbers. 



In Naples, in the year 1908, I met with a large holotrichous 

 Ciliate, which I am inclined to identify with Holophrya oblonga, 

 crawling on the stalks of Eudendrium. The Ciliate was found to 

 contain two kinds of Nematocyst absolutely identical with those of 

 the Eudendrium. It also contained large numbers of chromatin 

 granules, which I am inclined to derive from the partly digested 

 nuclei of the Nematoblast cells of the hydroid. A direct proof of 

 the origin of similar chromatin granules and Nematocysts in the 

 case of an Acinetaria Ophryodendron abietinum has been given by 

 me in my paper on this form in the Q. J. M. S., Vol. 53, 1909, 



"Ophryodendron abietinum was first discovered by Claparede 

 and Lachmann in 1855 on Campanularia from the North Sea . . ." 



"They recognised in the interior of some animals both of the 

 veriform and proboscidiform type small corpuscles 'tout a fait sem- 

 blables aux organes urticants des Campanulaires' (p. 144), but as 

 all their efforts to surprise the animal at the moment of feeding- 

 were vain (p. 145), they concluded that 'les corpuscles particuliers 

 qu'ils renferment sont peut-etre comparable aux trichocystes d'autres 

 infusoires'." 



XXXIV. 17 



