146 BULLETIN OF THE 



both intermediate and primary, although the tentacular bulbs at the ends of the 

 radial tubes are larger than the remainder. This predominance in size they 

 always retain. Fig. 1, Plate I., represents a young Lizzia, intermediate in 

 form between that figured by Forbes and the adult L. grata as given by ^Ir. 

 Agassiz. The addition of two more tentacles to the primary clusters completes 

 the number five and gives for the adult, as far as followed by any observer, 

 thirty -two tentacles in all. There appears, however, no satisfactory evidence 

 that this is the maximum number possessed by the adult, and possibly the in- 

 termediate clusters likewise iuci'ease to five tentacles instead of tliree, which 

 would give it a resemblance to the genus Rathkea of Haeckel. 



Lizzia passes through a Dysmorphosa and Margelliuvi stage, and has the 

 power of germination throughout them both. It seems, therefore, hardly 

 proper as yet to form new genera, as Haeckel has done, on what are surely 

 embryonic features. The genus Rathkea of Haeckel, or Oceania Blumenbachii 

 of Rathke, in the description and figures of the latter, has eight chymiferous 

 tubes. I do not feel justified in considering with Haeckel that four of these 

 tubes are folds of the bell or muscular fibres. There is one feature found only 

 in more advanced stages, which seems to be wanting in all the immature con- 

 ditions of the Lizzia. Four small bundles of oral knobs are formed on the 

 under side of the lips near the bifurcation of the oral tentacles. These make 

 their appearance at the same time that the second tentacle in the intermediate 

 clusters develops. Mr. Agassiz has given a good figure of them in the adult 

 proboscis (N. Amer. Acal., p. 162). 



The specimens of Lizzia, with buds in all sizes, which I have studied, were 

 taken abundantly in tide eddies in Laboratory Cove, at Newport, R. I. The 

 development of the egg is unkno^vn. At the junction of each of the radial 

 tubes with the stomach, in older specimens, clusters of small ovarian-like cells 

 ■were observed, which resembled undeveloped ova, but I was unable to defi- 

 nitely form an opinion as to their exact character. 



Mabella gracilis, n. g. & s. 



Plate VI. Figs. 2, 3. 



A single specimen of a very interesting jelly-fish was taken near the close of 

 the month of July. This medusa is of a genus as yet undescribed, and re- 

 sembles Dijsmorphosa very closely, with the exception (?) that it has eight radial 

 chymiferous tubes. Gemmation from the proboscis similar to that which has 

 been described in Lizzia, combined with the last-mentioned characteristic, 

 makes it a most interesting and exceptionable jelly-fish. The bell has the 

 shape of a very convex watch-crystal, the height of which is about one half its 

 radius. It is transparent, colorless, and the surface is covered sparsely with 

 small papilla). Tlie chymiferous tuljes are narrow, without side a]ipendages, 

 simple, and eight in number. Proboscis without a peduiicli', (luadrute, with 

 four undivided and non-bifurcated oral tentacles, which have their club-shaped 



