HOLOTHURIA. 53 



creature. All were spherical, the fifth or sixth of a line in diameter, of 

 an olive colour, and containing a dark speck in the centre. — Plate XL 

 fig. 0., portion of spawn sUghtly enlarged ; fig. 6, more enlarged. 

 When first observed, the ova seemed to be discharged from the acute or 

 posterior extremity of the animal, where the oviduct might have been 

 supposed to terminate. But it is not in that place, it is nearer the root 

 of the protruded tentacula ; nor do the ova thus escape. 



They then rose with such force as to reach the surface of the 

 water, two or three inches abo\'e that orifice ; and in falling, accumu- 

 lated below on the bottom of the vessel, around the curvature of the 

 body. Some were apparently aljsorbed in the orifice when they fell 

 down, and thence a second projection or apparent discharge ensued. 



However, on weighing all the concomitant circumstances, I was in- 

 duced to conclude, tliat the apparent absorption was onh' a reception — 

 an accidental one from the position, and the course of the organs and 

 the ova. 



We have already spoke of the stream ejected by the Holothuria 

 pentact.es, which may be of long continuance, from the absorbing and 

 discharging faculty : also of the probability, that the respiratory organs 

 are benefited by this process. Many aquatic animals, and among them 

 the Holothuria, give ocular demonstration of it, by the formation of a 

 vortex in their element. For this some are provided with external, 

 some with internal organs. But the observer must beware of delusion, by 

 the mere revolution of buoyant particles on a considerable surface, wliich 

 often ensues, particularly in open shallow vessels, from invisible currents 

 of air, alternations of temperature, and the Uke. 



A gentle vortex was sensible in the vessel of this Holothuria, on 

 the evening which preceded its spawning. In the next place, more 

 forcible resumption of the jet having disturbed the faUing or the fallen 

 ova, conducted them upwards by its force, and then some of them fell 

 back accidentally into the orifice, from which the water was discharged. 



Although the greater portion of the spawn formed a mass consist- 

 ing of ova imbedded in gelatinous matter, many floated separately 

 among the water. This happens frequently, either from their being free 



