No. 394.1] HYDROID FROM LONG ISLAND SOUND. 803 
the hydrorhiza in Hydractinia and Podocoryne. But there is a 
thick cushion of diatoms, simple alge, and other detritus which 
forms a mat over the ses 
surface of the shell and 
around the attached 
ends of the hydranths. 
It seems to collect be- 
cause the colonies are 
not tumbled about as 
in Hydractinia. The 
spines do not project 
beyond the surface of 
the mat and seem not 
to be efficient struc- 
tures in protecting the z j 
longitudinally; %., proximal part of a hydranth arising from 
ol ; 
warty They panei a tube of the hydrorhiza. The dotted area represents the 
probably vestigial. diatoms and other detritus which surround the base of the 
O. 
As stated above, C nae *3 
there are but two kinds of hydranths, the nutritive and repro- 
ductive. They are present in approximately equal numbers, 
and uniformly distributed among each other throughout the 
colony. Both were found in all 
stages of development. I have 
no evidence that either ever be- 
comes transformed into the other. 
As in other hydroids, the sexes 
are separate, the male colonies 
apparently being much more 
numerous than the female. Of 
eighty-three colonies observed at 
different times, sixty were male 
and but twenty-three female. 
The nutritive hydranths (Fig. 
ye (1)—(3)), when fully extended, Fre. 4. — Recently liberated female medusa, 
are perhaps more elongate than E a a A Pigeon 
those of any other marine hydroid — ^: “*n*#tlesi 7, velums om, ova. 50. 
heretofore observed. Each arises directly from the tubes 
of the hydrorhiza, and at the base is covered for a very 
pine cut 
