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



As an example of the evidence which Strethill Wright was 

 able to bring forward in support of his view, we may give the 

 fourth observation cited byGrosvenor from Strethill Wright's 

 work. 



"An E. Drummondii, found on Tubularia indivisa, had 

 nematocysts of the four kinds, found in the latter. Having fasted 

 for 'a long time', this specimen was fed on Coryne eximia. Next 

 morning its papillae and alimentary canal were crowded with the 

 cnidae of Coryite mixed with those of Tubularia." 



These observations were unfortunately completely overlooked, 

 with the result that Bergh in 1861 described the Nematocysts in 



Aeolids as being secreted 

 in the Cnidosac, and this 

 view was further develop- 

 ed by later workers, 

 whose papers have ther- 

 efore now only a historical 

 interest. 



Grosvenor sum- 

 marizes the result of his 

 own work on page 4b3 of 

 his paper. 



"The facts brought 

 forward as evidence that 

 the nematocysls of Aeo- 

 lids are derived from 

 their prey are as follows : 



(1) Not only are nem- 

 atocysts of Aeolids 

 and Coelenterates 

 identical in plan of 

 but each of several 



VII. 



construction and mode of discharge, 

 distinct types occurs in both groups. 



(2) A single type of nematocyst does not occur uniformly throughout 

 a species, but different individuals of the same species may 

 have quite different nematocysts; moreover, a single individual 

 may have nematocysts of several different types, found in as 

 many distinct species or groups of Coelenterates. 



(3) When it is known on what Coelenterate an Aeolid has recently 

 been feeding, the nematocysts of the two are found to be 

 identical. Also the nematocysts from the faeces of an Aeolid, 

 which are generally admitted to be derived from their food, 

 are always identical with at least some of the nematocysts 

 from the cnidosacs. 



