GENERAL NOTES. 419 
GENERAL NOTES. 
A FRESH-WATER HYDROZOON—Cordylophora lacustris (?) 
All—In the early part of March I went to the Petane (Esk) 
River, Hawke’s Bay, at a point near to the Napier-Taupo road, 
and about a mile from the place where, under ordinary circum- 
stances the river flows into the upper portion of the Napier Har- 
bour, to collect specimens,and if possible to find in particularsome 
more of the fresh-water Polyzoon, Plumatella repens,* which I 
had found on former visits. The afternoon was warm, and a 
gentle breeze carried my boat along over the clear water. Every 
floating piece of raupo was covered with small molluscs, and © 
others might be seen crawling slowly over the bottom. Here 
and there would be seen the furrow-like track of a Unio, and on 
nearing the mouth of the river swarms of crabs made with all 
speed for their holes in the clayey banks and mud flats. 
Being now in brackish water, I had given up hopes of finding 
my Plumatella, when I saw some rotten leaves of raupo covered 
with an interlacing network, and which, when looked at closely, 
resolved itself into something very much like the species I was 
in search of. I collected some of the best pieces and put them 
into a bottle with some water, and after finishing my other work 
took the specimens home. The first look at the animal con- 
tained in the little horny tubes which formed the network told 
me that it was among the Hydrozoa that I should have to look 
for my species, which differed chiefly from Hydra in having a firm 
outer case or ccenosarc. I found the specimen easy to handle, 
and upon cutting off a portion of the colony and placing it under 
the microscope, it condescended to dilate itself, and thrust forth 
one after another its restless arms and tentacles. The tentacles 
under all powers presented the same granulated appearance as 
those of the common Hydra, and, I fancy, show, when stained, a 
trace of muscular fibre. The polypite is, in shape, that of a more 
or less elongated oval, having at its apex the mouth-opening and 
from 15 to 20 tentacles, varying in length, disposed irregularly 
round it. The narrowed extremity or neck is inserted into a 
chitinous tube apparently excreted by the polypite from the 
ectodeimal layer. The gastric chamber can be plainly seen 
through the ectoderm, but the structure I could not determine 
at the time. One polyp, after stretching and expanding itself 
several times, gradually retracted the mouth until the thickest 
portions of the club formed the rim of a cup ‘by introversion, the 
tentacles during this manceuvre being shortened and dwarfed. 
It then gradually resumed its normal shape. I was unable to 
detect any particle of food or grain of irritating matter which 
might account for this strange movement. 
In my first gathering I did not observe any reproductive 
organs or buds, but in a subsequent occasion I collected several 
* Trans, N.Z, Inst., Vol, XII, p, 302. 
