MCMURRICH] THE ACTINIARIA OF PASSAMAQUODDY BAY 79 
the radial of the disk were both imbedded in the mesoglæa. I did not 
observe, however, any inclusion of the endodermal musculature of the 
disk in the mesoglæa. 
Two siphonoglyphs and two pairs of directive mesenteries were 
present and, in addition to these mesenteries, there were fourteen other 
perfect pairs in two individuals examined, making a total of sixteen 
pairs of perfect mesenteries, which were also sterile. Assuming that 
these represent two cycles, there was a third cycle of sixteen pairs which 
were imperfect and fertile, and thirty-two pairs of a fourth cycle, also 
imperiect and fertile. The members of this fourth cycle show the 
peculiarity observed by Carlgren. In sections through the uppermost 
part of the column no traces of the cycle can be seen, but about half 
way down one finds a single unpaired representative of it in each inter- 
space, between pairs of the first or second, and third cycles, these fourth 
cycle mesenteries having their longitudinal muscles on the side directed 
toward the pair of the third cycle. A little lower still and another re- 
presentative of the fourth cycle makes its appearance in each of the 
interspaces mentioned, forming a pair with the member already present, 
but remaining much narrower than its fellow throughout the rest of the 
length of the column. I did not, however, find representatives of the 
fifth cycle described by Carlgren. As regards the structure of the me- 
senteries and their musculature, these agree perfectly with the descrip- 
tion given by Carlgren and I have nothing to add to this except to say 
that the thickening of the mesenteries at their outer edges does not 
always occur and is possibly due to a certain amount of contraction. 

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