150 Transactions of the [SffiJfSnS 
to enter upon this interesting branch of vegetable morphology. He 
observes, for example, concerning certain leaves of the Piperaceae, 
that their internal structure appears to represent a branch with its 
posterior half atrophied; and he tells us that he determines the 
course of the ligneous bundles in each leaf by making numerous 
sections in all directions, and examining them with a pretty strong 
power. 
At the November meeting of the Society, Mr. Kent exhibited 
living specimens of Mysis vulgaris, captured in the Victoria Docks. 
Drawing attention to the constant motion of the outer divisions of 
the thoracic limbs, he considered it highly probable that they served 
for respiratory purposes, in which case the recognized affinity of the 
genus with the Branchiopoda would be still further substantiated. 
Professor Sars has, however, recently demonstrated that a species 
confined to the fresh-water lakes of Norway possesses a peculiar 
series of reservoirs situated on each side of the thorax, wherein the 
blood is for a time detained before re-entering the heart, and there 
reoxygenized by the constant current of water passing between the 
carapace and the walls of the body, which current is produced by 
the movement of the outer divisions of the thoracic limbs observed 
by Mr. Kent, in conjunction with that of the epipodite of the first 
pair of maxillipedes. 
Prof. Sars adds that he has by no means made out this system 
of reservoirs so clearly in the other species which he has examined 
— a circumstance which will account for its having hitherto escaped 
the observation of naturalists. 
In December, Dr. Carpenter favoured us with a lecture descrip- 
tive of his deep-sea dredging expedition, which resulted in important 
discoveries, confirming the views which Dr. Wallich expressed many 
years ago, and opening the way to new theories and fresh investi- 
gations. The deep-sea life discovered by Dr, "Wallich was quite 
sufficient to show that enormous pressure and the diminution of 
actinic rays at great depths did not involve the extinction of all 
life, as many eminent naturalists had supposed, or even the suppres- 
sion of forms as high as the starfishes. Dr. Carpenter's dredgings 
prove that temperature, and not pressure, or other incidents of 
depth, is the chief determining cause whether life shall flourish or 
fail. When the influence of the Gulf Stream raises the temperature 
of the sea-bed currents, life corresponding to the amount of heat 
appears to be developed ; and if at the same level the warm stream 
ceases and cold ensues, living forms become infrequent or disappear. 
The bearing of these researches upon various branches of science is 
highly important. The opinions held by many physiologists, that 
the sea had one uniform temperature at a certain depth is proved 
to be incorrect ; life processes, not only of the lowest animals, but of 
radiata, polyzoa, Crustacea, and mollusca, appear to go on satisfac- 
