MUSEUM OF COMPARATIVE ZOOLOGY. 157 
the tube, but as narrow folds along the whole length of the vessel. The 
stomach of a young Zygodactyla has a rectangular outline. Intermediate tubes 
really begin to form while there are but four tentacles, while the figure re- 
ferred to (N. Amer, Acal., Fig. 156) has four ch ymiferous tubes and twenty-four 
tentacles, 
The youngest Zygodactyla taken by me was captured with the drag-net in 
the last of June. It was a little more than an eighth of an inch in diameter, 
and is figured on Plate V. figs. 5, 6. The color of the bell on a black ground is 
pale green ; that of the tentacles, cream-white. The radial tubes broad, four 
in number, each one arising from an angle of the rectangular stomach, and ex- 
tending the whole distance to the bell margin. There are also rudiments of 
four other tubes, each of which arises from the side of the stomach midway 
between the pairs of primary tubes, and extends half the radius of the bell, and 
there ends abruptly in a slight enlargement. There are four tentacles corre- 
sponding with the tubes which are fully developed, and beginnings of four 
more, one midway between each pair of primary. The tentacles, as soon as 
developed to any extent, are coiled up when the animal is at rest, just as is 
the case in the tentacles of the adult, "The outer surface of the bell is crossed 
by four meridionally placed rows of lasso-cells. These diminish in size with 
the growth of the Zygodactyla, and in the oldest medusæ are almost com- 
pletely lost. No tubercles exist on the under side of the umbrella of a Zygo- 
dactyla as small as the example which I figure. Vertical outline of the 
Stomach rectangular. Development unknown. Although the ovaries were 
crowded with eggs, I was unable to raise any of them, and cannot tell whether 
it has a hydroid or not, except on the grounds of comparative embryology of 
other and similar meduse. Variations in the course of the tubes, their union, 
bifurcations, and number, are very numerous. In such cases of abnormal 
growths the ovaries which accompany the tubes follow the same variations. 
Tima formosa A. Aa. 
Plate VI. Figs. 1, 4, 5, 6. 
A Tima was very abundant at Newport, in May of the past year, which 
later in the season disappeared altogether. In former years, I have begun my 
work there in June, and have never had a specimen of Tima. These facts 
lead to the conclusion that the medusa is a spring jelly-fish in Narragansett 
ay. 
Tima formosa, A. Ag. is closely related to T. Bairdii of Forbes. Of the for- 
mer species, the only representative of the genus on our coast, Mr. Agassiz 
has given a good account, Larger specimens, with more tentacles than he 
mentions, were found, but in the main I have little to add to his description of 
the adult. He says that the otocysts have from four to five otoliths. "This 
number is too small. In mauy otocysts of young jelly-üshes ten to fifteen 
otoliths were counted by me. The otocysts often form new ones by a 
