FOUND IN THE NORTHUMBERLAND: LAKES. 41i 
The tentacles, Pls. VII. & VIIL. figs. 5,7, are of the flesh-coloured 
species, are very rough and beautiful, exhibiting an imperfect 
spiral arrangement of the nodular enlargements. There are two 
kinds of vesicles immersed in the nodules, as have been described 
in some other species; one being much more numerous and 
smaller than the other. The former are for touch, the latter for 
prehension, according to Corda, who appears to have examined 
these organs with great care, but whose description of one of 
them is erroneous in several respects: the original memoir, how- 
ever, I have not seen. Neither have I had an opportunity of 
consulting Ehrenberg’s account of the minute structure of the 
tentacles of these animals. The smaller vesicles, Pl. VIII. fig, 
7 a, and fig. 8, seem to agree with Corda’s description as‘given 
in Johnston’s “British Zoophytes ;” they are elliptical, being com- 
posed of an inner and outer sac, both very delicate, transparent 
and membranous. These bodies are placed with their long axis 
perpendicular to the surface of the nodule in which they are im- 
bedded, and have a non-contractile hair-like process projecting 
from the external end. 
The larger vesicles, fig. 7 6, are very complicated, and appear 
to have been only partially understood by Corda, though he had 
arrived at a full comprehension of their functions. They are 
not merely prehensile organs, but are undoubtedly also stinging 
instruments, as supposed by this naturalist, and are at least twice 
as large as those for touch: they, fig. 9, are of an ovate form, short 
and stout, immersed in the substance of the nodule, with the 
narrow end uppermost, and immediately beneath the surface. 
At the bottom of the vesicle, which, though perfectly transparent, 
has rather thick walls, is seen a delicate lining membrane, d, 
folded down upon itself, having a cup- or saucer-like appearance. 
This, according to Corda, is “a saucer-like vesicle.” Standing 
up from the centre of this, is a transparent membranous stalk, 
c, irregularly bulged a little at the sides, and surmounted by a 
sharp arrow-like head, 6, with the barbs much depressed. This 
supporting stalk is described by the naturalist, just quoted, as 
“a, solid, ovate corpuscle.” But to get a full knowledge of this 
apparatus, it must be examined when exserted and ready for 
