344 JOHN F. FULTON, JR. 



of sponge chlorophyll, while Brandt (1881 a, 1881 h, 1882, and 

 1883) supported the view that chlorophyll in the Porifera and 

 other animals results from a symbiotic association with green 

 algae. ^ Zooxanthellae — symbiotic holophytic flagellates — have 

 been reported for several sponges, also recently by Kirkpatrick 

 (1912) for Merlia normani." Cotte (1904) likewise gives 

 an account of an interesting association of this sort. 



There is no doubt but that Lankester had every reason to 

 question the evidence of Brandt — which in the light of later 

 investigations was most decidedly inconclusive — and he ' has 

 done valuable service by his championship of the opposed 

 view, that of the intrinsic nature of the corpuscles under 

 discussion. For his view compels those who hold the " algal " 

 theory to investigate each case separately and to vindicate 

 their view by the synthesis of the green animal ' (Keeble and 

 Gamble, 1907, p. 171). Now, however, there is little question 

 but that true chlorophyll in animals owes its existence in every 

 case to plants. It seems evident, therefore, that the pigmenta- 

 tion of most sponges has resulted from an association, symbiotic 

 or otherwise, with plant cells ; and that, as with the Protozoa, 

 the Porifera present no serious obstacle to the assmnption 

 that animal colour arises in the blood. Consequently a discus- 

 sion of the phylogenetic aspect of pigmentation must of 

 necessity commence with the coelenterates. 



3. COELENTERATA. 



Since the coelenterates are organisms having but two cell 

 layers, ectoderm and entoderm, it is at once obvious that they 



^ Since the present writing the work of Van Trigt (1918) has been brought 

 to the writer's attention. He has shown that in Spongilla the green cells 

 very clearly are invading organisms, and has made an extensive series of 

 experiments with cultures of the green cells derived from the macerated 

 sponge tissue. He has also given conclusive proof of an oxygen-carbon 

 dioxide exchange between the algal cells and the sponge tissue. His 

 evidence further corroborates the view just expressed concerning the 

 symbiotic nature of the green cells in sponges. 



- Winter (1907) has shown that Zooxanthellae are symbiotic in the 

 foraminifer Peneroplis. 



