MUSEUM OF COMPARATIVE ZOOLOGY. 173 
otocyst of Cyanea, Plate VII. fig. 19, c. The lateral tubes which enter their 
bases are strictly homologous to the earl y conditions of the lateral branches in 
the ephyra of Cyanea, Figs. 9, 10. That there is this resemblance between the 
marginal sense bodies of the young Cyanea and the adult Aurelia is still another 
fact added to many others, that Cyanea stands higher in the scale of life than 
Aurelia, or that Aurelia is an arrested stage of development similar to the 
young of Cyanea. 
Dactylometra quinquecirra, A. Ac. 
Plate VIIL Fig. 14. 
D. quinquecirra is a rare medusa in Narragansett Bay. One or two specimens 
are taken each summer, "The adult, one half natural size, is shown in Plate 
VIIL fig. 14. The genus is characterized by the presence of five tentacles 
between each pair of otocysts. In other respects it resembles Pelagia, to which 
genus it was referred by Desor, 
The umbrella is thickly pigmented with brown and red spots, which are 
very large in the middle of the upper surface of the umbrella. The color of 
the bell is pale blue and brown. The same color with pigmentation is likewise 
found on the tentacles, 
There are oral appendages of two kinds, four of which are quite long, float- 
ing gracefully along after the medusa as it swims in the water. The remaining 
oral appendages are shorter, more ruffled, confined to the immediate vicinity of 
the mouth, and extending only a short distance outside of the bell below the 
lower floor. The stomach lobes are united at their bases, yet not by a solid 
circular ring such as exists in Cyanea. Ovaries yellow, hanging in baglike 
masses between the pillars by which the oral appendages are suspended. In 
aleoholie specimens there are no eireular muscular folds such as exist on the 
lower floor of Cyanea. The whole umbrella is very flexible. Size six to ten 
inches in diameter. "There are gene "ally five tentacles between each pair of 
marginal sense bulbs. These tentacles vary in size, and oftentimes there are but 
three or four between each pair of otocysts. The chymiferous tubes resemble 
closely those of the genus Pelagia. They are not dendritic at their distal ends, 
as is the case with Cyanea, nor branched as in Aurelia, but pass directly to the 
vicinity of the otocysts, where they divide, sending a branch into the cavity 
of this structure, and lateral forks which are continued into a tube which runs 
along the margin of the disk. 
CTENOPHORA. 
Mnemiopsis Leidyi, A. Ac. 
M. Leidyi is one of the most common Ctenophores in Narragansett Bay. In 
the latter part of the summer and arly autumn these jelly-fishes fill the water 
in Laboratory Cove, Newport, and can be found in almost all stages of develop- 
