﻿Dec, 1857.] 



ELLIOTT SOCIETY. 



257 



yarious directions, at the will of the animal, like the protruberant 

 mouths of Corynidian polyps. 



About the same time, and in the same jar, I found another 

 young Beroid, larger in size and more advanced in structure, but 

 with such a resemblance to the foregoing, that I at once asso- 

 ciated them together, as different stages in the growth of the same 

 species. 



The body, now grown larger, was still, in the main, pyriform, 

 but like the Cydippe brevicostata of Will j it had two very distinct 

 labia, or lappets, on the oral extremity of the body, and in the 

 cleft between them was the oral orifice. The line of this cleft is 

 in the same plane with a line which we may suppose to connect 

 the two tentacular chambers above, making the position of the 

 lappets correspond to that of the wing-like expansions in full- 

 grown Bolinas. Changes had also occurred in other parts of the 

 body. The space between the sense-capsule and the apex of the 

 digestive cavity had notably increased, and with it the proportion- 

 ate length of the ascending diverticulum of the circulatory sys- 

 tem. The ambulacra had progressed further downward than in 

 the first specimens described, and with them the superficial tubes. 

 They had, in fact, reached half way down between the position 

 of their extremities in the first specimens and the mouth. The 

 tentacular chambers, also, were, relatively, lower down. 



At a later date, June 3d, I was so fortunate as to find a stage in- 

 termediate between these two. This specimen was not actually 

 measured, but its size was, judging by the eye, about the tenth 

 of an inch. Its general outline was still pyriform, but the mouth, 

 though not actually bilabial, was situate at the bottom of an 

 elongate depression, whose axis corresponded with that of the 

 cleft between the labia in the older of the two former specimens. 

 The tentacular chambers are still directed outwards, not down- 

 wards, having not, as yet, sensibly departed from the level of the 

 lateral sinuses. The ambulacral tubes which (as will be also 

 seen to be the case in Beroe,) in their progress downward, precede 

 the ambulacra themselves, had not, as yet, descended below them. 

 On the other hand, the two gastric tubes which, in the adult, de- 

 scended from the centre of the circulatory system, down along the 

 sides of the digestive cavity, to anastomose with the tortuous pro- 

 longations of the ambulacral tubes in the lobes, had, at this stage 

 of growth, already reached the borders of the mouth. The large 

 lateral sinuses, which were the principal portion of the circulatory 



