842 RORIDULA. Caap. XV. 
secretion being readily withdrawn from the glands; so 
that, when an insect comes into contact with a drop, 
it is able to crawl away, but soon touches other drops, 
and then, smothered by the secretion, sinks down on 
the sessile glands and dies. Another difference is, 
that the secretion from the tall glands, before they. 
have been in any way excited, is strongly acid, and ° 
perhaps contains a small quantity of the proper 
ferment. Again, these glands do not secrete more 
copiously from being excited by the absorption of 
nitrogenous matter ; on the contrary, they then absorb 
their own secretion with extraordinary quickness. In 
a short time they begin to secrete again. All these 
circumstances are probably connected with the fact 
that insects do not commonly adhere to the glands 
with which they first come into contact, though this 
does sometimes occur; and that it is chiefly the se- 
cretion from the sessile glands which dissolves animal 
matter out of their bodies. 
RoRIDvULa. 
Roridula dentata.—This plant, a native of the western 
parts of the Cape of Good Hope, was sent to me in a 
dried state from Kew. It has an almost woody stem 
and branches, and apparently grows to a height of 
some feet. The leaves are linear, with their summits 
much attenuated. Their upper and lower surfaces 
are concave, with a ridge in the middle, and both are 
covered with tentacles, which differ greatly in length ; 
some being very long, especially those on the tips 
of the leaves, and some very short. The glands also 
differ much in size and are somewhat elongated. 
They are supported on multicellular pedicels. 
This plant, therefore, agrees in several respects with 
