133 PROFESSOR E. VAN BENEDEN. 



of which any single cell is capable of reproducing the 

 whole, each cell contains the germs of all parts of the 

 organism. We shonld then find ourselves discussing the 

 properties of the protoplasm, not of a single cell, but of 

 the whole organism, in so far as it had not been adapted by- 

 some modification of structure to the performance of some 

 special function. 



In these remarks, which conclude his pamphlet. Professor 

 Strasburger makes his contribution, from the side of micro- 

 scopical research, to an explanation of the phenomena of 

 development, its principal point of interest being that the 

 molecules which Professor Strasburger regards as being the 

 structural units of protoplasm, though it must not be 

 forgotten that they themselves are of complex structure, 

 correspond very closely with the " physiological units" pos- 

 tulated by Mr. Herbert Spencer^ in his account of these 

 phenomena. 



Professor E. Van Beneden's Kesearches on the Dtcye- 

 MiD^.i (With Plate X.) 



Professor Van Beneden opens his monograph with a short 

 review of the work of his predecessors in this field, amongst 

 whom the chief were Krohn, Erdl, Kolliker, Wagener, P. J. 

 Van Beneden, the father of the present writer, and Ray 

 Lankester. He then tells us that for two months from 

 August, 1874, he devoted his whole time to an accurate inves- 

 tigation of these parasites, worjiing first at Ville Franche 

 and then at Trieste. 



The Dicyemidae have been found as parasites in the fol- 

 lowing Cephalopoda — Octopus vulgaris, O. macropus, Eledone 

 moschata. Sepia officinalis, S. biserialis, Loligo vulgaris, and 

 Sepiola Mondeletii ; they were formerly believed by Kolliker 

 to belong to a single species, to which he gave the name of 

 Dicyema paradoxum ; but this was shown not to be the case 

 both by Wagener and Claparede, and Van Beneden has 

 classified them as follows : — He applies the generic name 

 Dicyema to those forms which are commonly met with in 

 the Octopus, and of these there are two species, D. typus, 



1 'Principles of Biology,' vol. i, p. 183. 



1 Abstract by Mr. D'Arcy Power, Exeter College, Oxford, of a Memoir 

 published in the ' Bulletins of the Royal Academy of Sciences,' of Belgium. 



