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PROCEEDINGS OF THE 



[April, 1857. 



a quadrate aperture. This reminds us of the corresponding dis- 

 crepance between the numerical formulae of the mouth and sexual 

 organs in Cladonema, observed by Dujardin; but I have not been 

 able to ascertain whether it is constant for all the specimens. 



With regard to coloration — the peculiar ornamentation of the 

 external surface, gives the animal a rich and obscurely frosted ap- 

 pearance. With this exception, the disk is colorless. The 

 coloration of the digestive trunk is a combination of a deep red, 

 with a rich orange, the lining membrane of the stomach being of 

 the former color, and the sexual lobes of the latter. The red 

 color characterizes also the opaque portion of each ocellary bulb, 

 and to a rather less degree, the lining of the cavity in the terminal 

 bulb. The transparent tissue surrounding these parts in both ca- 

 ses, is of the orange tint. The shaft of the tentaculum mostly col- 

 orless, but having occasionally, near the terminal bulb, a few fleck- 

 ings of lake color. The pads of thread-cells have a whitish frosted 

 appearance, which is peculiarly rich and agreeable to the eye, 

 and which resembles that on the whole outer surface of the disk. 

 These pads, and the external surface of the terminal bulb, are 

 always bristling with innumerable points, which are the lashes of 

 the thread-cells. 



In comparing this figure of the adult (fig. 3) with the figures 

 of the young, (fT. 5, 6, 7, 8,) we cannot but be struck with the 

 fact, that in the young, (fig. 5,) the bell-wall is throughout thin, 

 and that no trace exists of that complicated system of arches de- 

 scribed in the adult as serving to suspend the digestive trunk. 

 This constitutes one of the most marked distinctions between the 

 bi-tentaculate and adult stages. Besides the difference of form 

 already noticed, the animal, in its bi-tentaculate stage, has a 

 bright lake nucleus just in the centre of the base of the digestive 

 trunk whence spring the radiate tubes. It is at this stage appa- 

 rently so awkward in its motions as almost to provoke laughter. 



The coryne, which bears this Medusa, is rather rare, as is also 

 the Medusa. It is found growing on sponges a little above dead 

 low water mark. It has been found during the summer months, 

 and whether or not it exists during the winter, (as in all proba- 

 bility it does,) has not been ascertained. A young bi-tentaculate, 

 but free Medusa, has been taken as early as the 5th of June. A 

 fully developed specimen has occurred in the end of July, while 

 as late as the 12th of September, buds were still produced from the 

 coryne, fT. 6, 7, and 8, having been drawn at this date. This leads 



