556 Records of the Indian Museum. [Vo,. XI, 
The latter may have originated as a bud. Of the two the terminal 
bulb possesses thicker perisarc and more contracted coenosare and 
appears, though not the larger, to be the older individual. 
Significance of the Basal Bulb. There is no direct evidence as 
to the reproductive function of the basal bulb: no young hy- 
dranths have been observed springing from the coenosare of an 
old bulb, unless it be that where two basal bulbs occur on one 
hydranth, one represents the original bulb from which the hy- 
dranth grew while the other is a development of the hydranth 
itself. 
But the evidence of the structures and development of the 
bulb seem to point clearly to reproductive function. Thus the 
disappearance of the ectoderm at the junction of bulb and hy- 
dranth seems to be analogous with the similar retrogression in 
the sporosacs of Dicoryne and to indicate a regular preparation for 
the breaking away of the hydranth. An example of a recently 
released hydranth has been observed. Again basal bulbs are fre- 
quently found alone, and in these the coenosarc is in good preser- 
vation. Here we seem to have a parallel to the conse1ving power 
of the stolon as exhibited in the hydrorhiza of Dicoryne conybearet 
(Allman) in which, by the development of partitions of chitin within 
the lumen of the stolon the coenosare is preserved unharmed in 
various sections during unfavourable conditions (see Ashworth 
and Ritchie, 1915). In D. conybearei the conservation of the 
coenosarc in this way is succeeded so soon as favourable conditions 
return, by a new development of hydranths produced by the coeno- 
sarc; and it seems highly probable that a similar recrudescence 
of hydranth life arises from the coenosarc of the basal bulb. 
THE RELATIONSHPS OF ANNULELLA GEMMATA. 
I have already drawn attention to the curious combination in 
Annulella gemmata of peculiar characters some of which have been 
found rarely, and generally one at a time, in other species. The 
most accurate conception of the significance of these resemblances 
will be attained by a short comparison of each with its analogues. 
UNATTACHED HyYDROIDS. 
Several genera of Hydroids share with the Pennatulid and a 
few other types of Alcyonarians, the character of gaining a more 
or less insecure anchorage by simply embedding their proximal 
end in the mud of the sea-floor. They are generally characterized 
by solitary habit and by the weak development or absence of perisare. 
Amongst such are to be reckoned the Corynids—Myriothela and 
Blastothela ; the Pennarid, Heterostephanus ; and the Tubularids— 
Corymorpha, Lampra, Gymnogonos, Monocaulus and Branchio- 
cerianthus. It is probable that with these should also be grouped 
the lake forms—Moerisia and Caspionema. Many of these gain 
firmer anchorage by the development of ‘‘rootlets,” but the 
