154 BULLETIN OF THE 



do not show this protuberance, for the reason that the specimens which he 

 drew had the proboscis more or less protruded outside the bell cavity. The 

 external surface of the bell in the adult is smooth, and in the young is crossed 

 by eight meridionjd lines of cells, two of which arise from each tentacle 

 and extend to the pole of the bell, where all have a common junction. The 

 radial tubes ai'e narrow, thread-like, and not " wide," as McCrady says. They 

 are four in number. The proboscis is without peduncle. McCrady gives a 

 long description of what he calls a cellular upper portion of the proboscis, which 

 resembles a peduncle as found in some other medusaj. This cellular structure is 

 in reality the inverted upper part of the bell cavity of a Turritopsis in which the 

 proboscis has been extended outside the bell opetung. The bell of this genus 

 is often reversed, so that the whole of the proboscis with attached ovaries is 

 pushed out exterior to the bell, just as takes place in other genera, as Eucope 

 and Obelia. As a result of this protuberance of the proboscis, the upper part of 

 the bell is infolded and pressed into a " cellular body,'' like a peduncle. In 

 normal positions of the medusa the proboscis has no such peduncle. 



The ovaries are large, and arranged in four lobes, which cover the whole up- 

 per part of the proboscis. Their color is orange. Of oral tentacles there are 

 four, each one of which is subdivided into two parts at the extremity, and cov- 

 ered with very peculiar kiiobs, mounted on short retractile, thread-like pedicles. 

 These knobs, as McCrady pointed out, give to the extremity of the oral ten- 

 tacle a " frosted appearance." They are characteristic in their form of the 

 genus Turritopsis. A few of the same kind of pedunculated cells are found 

 near the first bifurcation of the oral tentacles, but the most of them are con- 

 fined to their extremities. The tentacles are numerous, with a length twice 

 the height of the bell, hollow, flexible, and clavate at their extremities. When 

 at rest they are coiled around the base, not unlike the position assumed by the 

 tentacles of Trachynema digitale, A. Ag. The number of tentacles in the oldest 

 specimen is thirty. The tentacular bulbs are so closelj'- crowded together that 

 intermediate sections of the margin of the bell cannot be seen, or are so very 

 small that the tentacular bulbs appear to touch each other. 



Otocysts wanting. 



Locality, Newport, R. I. 



1 have not noticed in the jelly-fish the zigzag motion which is mentioned by 

 McCrady, but the move'ment was always direct, consisting of several succes- 

 sive rapid contractions of the bell and veil, and then a pause followed at a 

 sliort interval by similar exertions. McCrady says Turritopsis is gregarious. 

 It is found accompanied by large numbers of the same kind, but cannot be 

 said to be more gregarious than many other jelly-fishes. Accumulations of 

 many in one place are due to tide eddies. 



The younger stages in the growth of the medusa have been well figured by 

 Mr. Agassiz. A few interniodiate stages are given by me to fill up the gajis in 

 the (levelojjmental history (Plati- IV. tigs. 4, (>, 7, 1), 10). Fig. <) is a niagnitied 

 view of one of the ])eculiar knobs found i)rinci pally on the extremities of the 

 oral tentacles, and characteristic of the genus. 



