118 SEA-SIDE STUDIES. 



point. As to there being an habitual communication 

 between the general cavity and the external water, 

 through these openings, M. Quatrefages peremptorily 

 denies it, without assionino- his reasons. His mere as- 

 sertion is of weight ; but for the present I am strongly 

 inclined to believe there is an habitual communication, 

 because, besides ova, I have seen the diffusion of chyl- 

 aqueous globules in the water, on the glass slide bear- 

 ing a Nereid. 



That an animal should suck up water into his body 

 is intelligible enough ; the water may serve for pm-poses 

 of aeration, nutrition, locomotion, &c. : it may give the 

 blood its oxygen, the tissues its organic substances in 

 solution, the shell its salts, and it may serve as a ful- 

 crum for the animal's progression. But when it is 

 pressed out of the body — as in some animals it is with 

 great frequency and raj^idity — will there not be a spon- 

 taneous phlebotomy, of a rather dangerous nature ? 

 That is the question. Hereafter (Part IH., Chap. H.) 

 we shall have to consider more closely the relation of 

 sea water to the circulating nutritive fluids ; for the 

 present let us be content with the idea that, in at Least 

 three divisions of the animal kingdom, water directly 

 mingles with the blood, and quits it en masse, csnTying 

 some blood with it. . 



