6 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 
motionless for a long time, and one is almost forced to compare it with 
a round flat table supported upon numerous legs. 
This medusa makes its appearance on the southern coast of New Eng- 
land at about the first of August. The diameter of the disk is then 
about 50 mm., and there are only three tentacles between each succes- 
sive pair of eye spots, so that it might well be mistaken for a Chrysaora, 
were one unacquainted with its future development. The medusze 
increase both in size and numbers until about the middle of Septem- 
ber, after which time they begin to disappear, although a few may still 
be found as late as the middle of October. The diameter of the disk of 
the full grown medusz is often as great as 250 mm. In common with 
many other Discophore this species seems to prefer the relatively im- 
pure water of bays and narrow estuaries. It is very common in the 
upper reaches of Narragansett Bay near Tiverton, while in the relatively 
purer water of the lower bay it is generally rarer. 
The medusa has also been found at Nantucket (Desor); Naushon 
(A. Agassiz) ; Bermudas (A. 8. Bickmore) ; between the Bermudas and 
the Azores (J. Drayton) ; and a well marked southern variety from Beau- 
fort, North Carolina (W. K. Brooks). 
Two species of fish have been found to accompany this medusa; one 
of these is a Clupeoid, and the other is the young of the common 
Butterfish (Stromateus triacanthus). These fish constantly crowd about 
the medusa, and so persistent are they in following the jelly-fish that 
they often allow themselves to be dipped up in the net along with their 
companion. 
The relations between the fish and the medusa, however, are far from 
symbiotic, for the fish gorge themselves with fragments of the tentacles 
and oral fringes, which they tear off from time to time. The medusa, on 
the other hand, is not wholly unavenged, for every now and then it suc- 
ceeds in stinging to death and devouring one of its persecutors. The 
fish which possess this curious habit are rarely more than an inch in 
length. 
An interesting abnormal specimen of Dactylometra quinquecirra was 
found at Tiverton, Rhode Island, in September, 1896. In this individ- 
ual there were three oral fringes, six genital organs and sub-genital pits, 
twelve marginal sense organs, forty-eight marginal lappets, and thirty- 
six tentacles (three between each successive pair of marginal sense 
organs). 
