﻿Dec, 1856.] 



ELLIOTT SOCIETY. 



67 



tion. Its position, also, at the border of the disk is worthy of es- 

 pecial notice, for the habitual position of the tentaculated larvae is 

 on the sides of the proboscis of the parent, or clinging to the inner 

 surface of the upper part of the swim-bell, and in no other instance 

 have 1 been able to satisfy myself that there was any adhesion to 

 the tentaculiferous border. Just within the cavity, and almost on 

 the border of the vail, it clung with such tenacity that, notwith- 

 standing the powerful contractions of the parent, by which it 

 would be thrown, now within and now without the opening of the 

 swim-bell, its hold was never lost. Yet it appeared to be in con- 

 tracted condition from the constant irritation to which, by its posi- 

 tion, it was subjected. From the same cause I was prevented 

 from making any thing but an outline, opportunity for which was 

 given me by a very short interval of repose in the parent. The 

 condition of the digestive cavity was not observed. That portion 

 of the body which contains the stomach, however, in the more 

 developed larvee, was large and nearly globular, having near its 

 upper surface obscure and somewhat irregular tubers, which may 

 have been either the buttons formed by contracted tentacula, or 

 the first appearance of developing tentacula. To the latter con- 

 struction I strongly incline, from the fact that I have never observ- 

 ed a larva of Turritopsis to adhere by any other part of the body 

 when the tentacula were unmistakeably developed, nor have I, in 

 any instance, observed the larval tentacula to contract in any 

 degree approaching to disappearance. These considerations, in 

 the absence of better proof, render it probable, and I, therefore, 

 believe that I have found in this specimen one of the earliest 

 stages of the embryo. 



The next stage of the growth is represented in fig. 20, PI. 6. 

 Two long flexible tentacula have sprouted from the upper or (with 

 reference to the oral extremity) the posterior side of the stomachic 

 bulb. A well defined digestive cavity occupies the centre of the 

 bulb, and is prolonged in a blind oesophagean canal to the oral 

 extremity of the proboscis, which has not been yet perforated by 

 the formation of a mouth. The tentacula are solid, and terminated 

 by a bulb exactly resembHng, in structure, that of the adult Turrit- 

 opsis. The axis is composed, as in the adult, of a pile of com- 

 pressed coin-shaped cells, capable of contraction and elongation. 

 This is covered by a cellular transparent sheath, in the outer 

 surface of which are many thread-cells. These are so numerous 

 on the terminal bulb as, in the end, completely to cover it; but I 



