A 
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BIGELOW: COAST WATER EXPLORATION OF 1913. 311 
to this (Fig. 74). The directive influence which causes the regular 
erect growth must be overcome in such a case since two of them grow 
in a diametrically opposite direction. There seems to be no hindrance 
to the growth of the hydranths, as they are found in various stages of 
development as well as in the adult condition, and when they were 
preserved several of them had undigested food in the enteric cavity. 
The development of the gonophore is not interfered with either, as 
medusae of different ages are found in the gonangia and some free 
medusae were found just liberated in the plankton. All the gono- 
phores were found either on the stolon or on original pedicels, none on 
the regenerated portions. 
Regeneration is no new thing in hydroids as it has been noticed by 
many observers, but I know of no case where anything on such a large 
seale as this and in such a location has been recorded. It is quite 
possible that some of the experimental work that has been done on such 
forms as Tubularia crocea and Hydractinia echinata would have given 
more satisfactory results if it had been done on Clytia cylindrica. 
It may be that the election of gymnoblastic forms for such experiments 
jmight have been improved upon by taking some of the simple calypto- 
blastic species. I am very doubtful if under artificial conditions in 
jany case regeneration could be successfully brought about in over 99% 
of the cases as it must have been here if one is to judge from the 
generous sample that was collected. 
Obelia geniculata (Linné).. (Fig. 75-78). 
| As this is a cosmopolitan form and as it has been described and 
ti gured in so many instances, a description of a typical specimen from a 
\ pical locality is quite unnecessary, but as many of the specimens in 
his material are not typical and as the location is unique, mention is 
_ specially made of the species here. 
| Two lots of specimens were present, both attached to eelgrass. In 
e case the stolon ran irregularly along throughout the whole length 
the fragment of eelgrass, on both sides, making rather a dense mass. 
i the other case a few colonies were distributed among several colo- 
tes of Sertularia cornicina. I do not know that O. geniculata is com- 
only found on eelgrass, as I do not remember having found it 
tere, or of having seen it recorded as so growing, but it does grow on 
¢ tain Algae and hence the difference in the nature of the support is 
‘Tt sufficient to make this case remarkable. Other species, e. 9., 
a 
