VITALITY OF ACTINIA BERMUDENSIS 359 



The presence of chlorophyll in aminal tissues has been repeat- 

 edly demonstrated. Among the Protozoa its occurrence is a mat- 

 ter of common knowledge (Salhtt, '84; Lankester, '85). By 

 means of the spectroscope Lankester as early as 1868 had made 

 it clear that chlorophyll was present in at least one sponge (Spon- 

 gilla fluviatilis) ; later, the investigations of Sorby ('75), MacMunn 

 ('88), and Krukenberg ('84) established the presence of chloro- 

 phyll in seventeen other species of sponge. In the coelenterates 

 chlorophyll is not to be found as a separate animal pigment, but 

 as chromatophores of intruding algal and protozoan cells. A 

 similar condition exists among certain of the marine Turbellaria. 

 The question as to whether or not these intruding algal cells are 

 photosynthetically symbiotic has excited great interest and not a 

 little dispute; it is a question, moreover, which, as far as the coelen- 

 terates are concerned, has never been satisfactorily settled. 



The presence of ' yellow cells ' in the body of sea-anemones and 

 of radiolarians has long been known. Johannes Miiller held 

 at first that they were concerned in the reproduction of the Radi- 

 olaria, while Haeckel ('62, p. 136) assigned a nutritional function 

 to them, comparing them to wandering liver cells. Cienkowski 

 ('71) was the first to look upon these organisms as parasitic 

 algae. He showed that they not only could survive the death of 

 the anemone, but could also live and reproduce outside the ani- 

 mal body. Richard Hertwig ('76) refused at first to accept 

 Cienkowski's conclusion that the 'yellow bodies' were parasitic, 

 believing that they were a part of the animal tissue; later, how- 

 ever, the brothers Hertwig ('79), and still later 0. Hertwig ('83), 

 abandoned this view on confirming Cienkowski's observation 

 that the organisms were capable of an independent existence. 

 This observation was further confirmed by Brandt ('81 b). Ged- 

 des ('82) proved that the 'yellow cells' from Anthea cereus give 

 off oxygen in the presence of sunlight ; however, he was unwilhng 

 to admit (as was also Lankester, '82) that the cells were parasitic; 

 but held, with Richard Hertwig, that the animal was capable of 

 manufacturing its own chlorophyll. This view was vigorously 

 opposed by Brandt ('81 a), who was so thoroughly convinced of 

 the parasitic nature of these forms that he established the genus 



