ANIMAL CHLOROPHYLL 845 



can possess no blood-system in the sense in which it is used for 

 the higher animals. Nevertheless, as Griffiths (1892, pp. 128 

 and 184) has emphasized, the nutritive or ' chylaqueous ' fluid 

 is analogous to the blood of the higher forms in that it carries 

 nourishment, supplies oxygen, carries off the waste products 

 of metabolism, and in many cases, as Kollmann (1908) and 

 others have since shown, is a corpusculate fluid. The impor- 

 tance of this analogy between the chylaqueous fluid and the 

 blood of higher animals is uncertain ; however, a question 

 immediately presents itself concerning the relation of this 

 fluid to the pigmentation of the coelenterates. It is therefore 

 desirable to consider first the nature of coelenterate pigments. 

 The animals on which the greater share of my work has been 

 done are two species of actinians common in the Bermuda 

 Islands: Condylactis passiflora Duch. and Mich.,^ 

 and Actinia bermudensis Verill. 



(a) Condylactis passiflora. 



Condylactis occurs in great abundance in all parts of the 

 Bermudas, and is usually found firmly attached to the under 

 side of rocks and in crevices just below the level of low tide. 



If the gastro vascular (chylaqueous) fluid of Condylactis be 

 withdrawn at any point on the body with a hypodermic 

 syringe and examined, two types of cell are usually to be 

 observed : one a yellow cell with several large grannies, and 

 the other, an unpigmented element. The pigment cells of 

 this body-fi-uid might easily be confused with wandering 

 pigment cells of the body-wall. In reality, however (as Eand, 

 1909, has noted) these cells are Zooxanthellae, and it is this 

 fact which in part explains a very striking phenomenon pre- 

 sented by a fresh smear of the gastrovascular fluid : viz. the 

 very marked oscillation of the individual cells. These yellow 

 cells (Zooxanthellae) gyrate usually in a counter-clockwise 

 direction on a single axis, while the colourless cells as a rule 



1 For an excellent description of this species McMurrich's (1889) paper 

 should be consulted. 



B b 2 



