170 
Recent Progress in our Knowledge of 
have rendered it hopeless to try to confine it within reasonable 
limits. I have already described its front. In the middle of the 
animal and close to the side was a contractile vesicle, Fig. 2, b, which 
opened and shut every two seconds or so. There was a clear space 
c at the end, but this I did not see contract. The shaded portion 
e might have been a stomach, but this I could not determine. The 
whole of the surface was spotted with granules, and was such as to 
impair greatly the definition of any internal organ. There was an 
anus at the side, towards the end opposite to the mouth ; and twice 
I saw the creature dart up the tube (so as to bring the vent above 
the top of it), shoot out its excrement, and instantly dart back 
again. 
The groups in Fig. 3 are carefully copied from two that were 
together on the same leaf, and which retained some of their 
inhabitants for about four days, and then dropped to pieces 
gradually, and disappeared in about four days more. 
II. — Recent Progress in our Knowledge of the Ciliate Infusoria. 
By G. J. Allman, M.D., F.R.S. 
Plate CXYIII. 
I believe that the object contemplated by the addresses which it 
has been the custom of your Presidents to deliver year after year to 
the Fellows of the Linnean Society will be best fulfilled by making 
them as much as possible the exponent of recent progress in bio- 
logical science. The admirable addresses with which my distin- 
guished predecessor has during his long tenure of office so greatly 
enriched our journal, afford an example as regards the exposition of 
botanical research which may well be followed in biology generally. 
The field, however, which thus offers itself is so wide, the activity 
in almost every department so intense, that the necessity of restrict- 
ing the exposition within a limited area becomes imperative if it be 
expected to produce anything like a definite picture instead of a 
EXPLANATION OF PLATE CXVIII. 
Fig. 1. — Strombidium sulcatum. 2 a. Crystalline bodies which have been liberated 
from it, and show amyllaceous reaction with iodine. After Biitschli. 
„ 2. — Polykricos Swartzii. 2 a. Thread-cell-like body liberated from its outer 
layer. 2b. The same with the filament ejected. After Biitschli. 
„ 3. — Torquatella typica. After Lankester. 
„ 4. — Silicious lattice-like case of a Dictyocysta. After Haeckel. 
„ 5 . — Didinium nassutum. 5 a. The same in the act of seizing a Paramcecium. 
5 b. The same with the prey passing through the oral orifice into the 
interior of the body. After Balbiani. 
