
No. 427.] C@LENTERATE FAUNA OF WOODS HOLE. 555 
were taken about the docks of the fish commission during 
July, and. even August, which were sexually mature, and 
from some of which ova were obtained and the develop- 
ment followed as described below. That these were not an 
isolated few left over from the earlier numbers of April and 
May is evident in that many were taken in the open waters 
of Vineyard Sound, and even in the open sea far from land 
in the region of the Gulf Stream, mostly of the genus Cyanea. 
They may have been caught up by southward currents from a 
more northern locality along the coast of Maine or beyond, 
and carried to these southern ranges. 
Specimens taken into the laboratory and placed in aquaria 
discharged developing ova in great numbers, literally covering 
and packing the bottom of the aquaria. The following synop- 
sis of the development of Cyanea may not be without interest 
as having been carried on under the wholly artificial conditions 
of the aquarium, from the later cleavage of the egg on to the 
freeing of the ephyrae, — a circumstance not hitherto recorded, 
so far as I am aware, though Bumpus has recorded the fact 
that earlier phases occur readily under such conditions, and 
both McMurrich and. Hyde likewise refer to the same fact, 
but they do not seem to have succeeded in tracing the entire 
development. 
The early cleavage phases of Cyanea are passed while the 
ova are still within the gastric cavity or while “ nursed " within 
the ample folds of the manubrium or frilled oral margins. 
A typical blastula results from total and regular cleavage and 
appears to be followed by an early gastrulation.and the prompt 
obliteration of the blastopore. 
Soon after this, and while the larvze are still within the egg 
membrane, cilia are developed, and they may be seen slowly 
rotating within the membrane, which, however, is early rup- 
tured and the embryo escapes as a free-swimming organism. 
In shape it is at first almost spherical, but soon takes on the 
oval or pyriform shape characteristic of most planule. Details 
as to the origin and differentiation of the endoderm are not 
yet worked out, but they seem to conform rather closely with 
the observations of Hyde and the later conclusions of Smith 
