112 SEA-SIDE STUDIES. 



and inasmuch as these eggs may be seen floating in the 

 general cavity of the body, before they issue through the 

 openings at the side, there seems little room for doubt on 

 the point. As to there being an habitual communication 

 between the general cavity and the exteraal water, through 

 these openings, M. Quatrefages peremptorily denies it, with- 

 out assigning his reasons. His mere assertion 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 diff'usion of chylaqueous globules in the water, on 

 the glass slide bearing a Nereid. 



That an animal should suck up water into his body is 

 intelligible enough ; the water may serve for purposes 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 fulcrum for the 

 animal's progression. But when it is pressed out of the 

 body — as in some animals it is with great frequency and 

 rapidity — will there not be a spontaneous phlebotomy, of a 

 rather dangerous nature ? That is the question. Wiser 

 lieads may answer it ; enough for me to have propounded it, 

 and to have called the reader's attention to a point very 

 interesting in the history of the development of the animal 

 series. Hereafter (Part ITI., Chap. II.) we shall have to 

 consider, more closely, the relation of sea-water to the cir- 

 culating 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, carrying some blood with it. 



