358 
BULLETIN OP THE BUREAU OP FISHERIES 
medusae in the act of releasing their ova are taken in abundance from the early part 
of June (McMurrich, 1891) until September (Sumner, Osburne, and Cole, 1913a, 
p. 575). 
North of Cape Cod it seems that the ephyrae of Cyanea are liberated later in 
the season, corresponding to the more tardy vernal warming of the water. I 
have no direct data as to the precise season when the ephyrae are set free in the 
Gulf of Maine, 98 for we have never seen a young Cyanea in the inner parts of the 
gulf during the spring months, but the few we have taken there during the last half 
of June have been only 2 to 3 inches broad (e. g., north of Georges Bank, June 25, 
1915, station 10298). It is not until the first part of July that we have seen Cyanea 
as large as 6 to 10 inches in diameter in the Massachusetts Bay region, pointing to 
April and May as the season when their liberation commences. At that time the 
smallest medusae of Cyanea must be extremely plentiful along the shores of the gulf. 
Alexander Agassiz (1865, p. 45) saw great numbers of them measuring to 3 inches 
in diameter on the surface in Provincetown Harbor in the early morning, all, however, 
sinking as the sun rose, and we have found them in abundance on Nantucket Shoals 
in April (p. 359). Our failure to take them in our tow nets elsewhere in the gulf 
during those months, in spite of the considerable number of hauls, recalls Louis 
Agassiz’s remark (1862, p. 109) that “there must be something peculiar in the habits 
of the young Cyanea to render them apparently so rare, when in the adult state they 
are so common” along the coasts of Massachusetts Bay. His suggestion that they 
keep near the bottom during their early stages has been corroborated by Mayer’s 
(1910, p. 600) observation that young Cyaneas rarely come to the surface in the 
aquarium but spend most of their time clinging to the bottom or side of the tank 
with their widespread oral fringes. The tendency of the small Cyaneas to seek the 
surface so much more regularly about Woods Hole than in the Gulf of Maine is an 
interesting local difference in habits still awaiting explanation. 
It seems that Massachusetts Bay and the Gulf of Maine generally offer an 
especially favorable environment for the Cyaneas, which grow so rapidly there that 
many of them attain a diameter of 2 to 4 feet by the close of the summer. This is 
about the average size at the end of their lives, though Alexander Agassiz (1865, p. 44) 
records one monster from Massachusetts Bay that measured 73^ feet across the disk, 
with tentacles upward of 120 feet in length. 
It is certain that the breeding season for Cyanea endures from June until mid- 
autumn in the Gulf of Maine, for on the one hand Hyde (1894) obtained developing 
eggs near Cape Ann early in summer, while on the other we have frequently found 
the medusae, with mature eggs and carrying great numbers of the planulae, cast up 
on the beach in September and early October. Probably Cyanea becomes sexually 
mature as soon as a certain size is attained, regardless of the precise season when 
this takes place, and continues to produce eggs or sperm throughout the remainder 
of its life, with the autumnal storms, which either cast the medusas on the shore or 
batter them to pieces at sea, setting the natural period to their existence. We find 
no record of Cyanea in the Gulf of Maine after October. 
»> One ephyra was taken near Mount Desert on June 14, 1915, but it was probably among the latest produced there. 
