﻿April, 1857.] 



ELLIOTT SOCIETY. 



189 



ble rapidity for a short distance; then comes a period of apparent 

 rest, in which it generally sinks, but still possesses sufficient con- 

 trol over its motions to throw its train of tentacula into various 

 curves, while they float in the wake of the disk, in such a manner 

 as to spread them over a greater surface than could be the case 

 when stretched in a straight line behind it. The motions by which 

 the animal thus steers its course in sinking must be very slight, for 

 I have not been able to observe them. However, it is perhaps 

 effected by employing the mechanical friction of the tentacula 

 against the water, as a means of partly arresting the gradual fall 

 of one side of the disk, while the other side is allowed to fall 

 almost with the full force of gravity by a continual lengthening of 

 the tentacula issuing from it with such rapidity that their friction 

 is not felt until they have reached the limit of extension. 



I have not yet been so fortunate as to meet with the larva of this 

 Medusa. 



This is a spring, summer and fall species. I have found it from 

 the middle of May, from time to time, until the beginning of No- 

 vember. With the exception of Hippocrene Carolinensis, we have 

 no more common species. 



EUTIMA, nov. gen. 



Characters the same as those of Eucheilota, with the exception 

 that thr> gelatinous disk is developed from the centre of the cavity 

 of the bell into the form of a more or less long conical appendage? 

 at the extremity of which is the digestive cavity, of the same 

 character as the corresponding part in Eucope. The four radiate 

 chymiferous tubes, originating at the base of the digestive cavity, 

 ascend the external surface of the conical appendage and arching, 

 connect themselves in the disk-margin with the circular tube as 

 usual. Sexual organs linear in form in the course of the radiate 

 tubes. Disk-margin with more or less numerous tentacula, whose 

 basal bulbs like those of Eucope, are provided each with two lateral 

 accessory tentacula, and two concretionary capsules between every 

 two radiate tubes as in that genus. 



The embryology of this genus is not yet known. Judging from 

 its close resemblance in all essential points to Eucope, it is hardly 

 probable that its larva will be other than a Campanularia. 



strokes to carry it the same distance, than is required by the former. This of 

 course, is what might be expected a priori, since the mechanical impulse given 

 by a single stroke of the deep bell must be greater than that of a single stroke 

 of the shallow bell. 



