438 Proceedings of the Royal Society 
fallacies might arise because of the long interval that often elapses 
between the administration of the poison and the appearance of 
tetanus. Experiments were made in some of which the blood- 
vessels of one posterior extremity, and in others of both, were tied 
before atropia was administered, and, by frequently modifying the 
dose, tetanus was on several occasions produced sufficiently soon to 
give results that were not materially influenced by the previous 
ligature of vessels. It was observed, in these experiments, that 
spasms and tetanus occurred in the limbs to which the access of the 
poison had been prevented, during the stage in which the nerves 
of the poisoned regions were regaining their functions. This is 
sufficient to demonstrate that the tetanus does not depend on an 
action on motor or sensory nerves, nor on muscles ; and it is, there- 
fore, apparent that it must depend on an action on the central 
nerve-organs. The predominence of cerebral symptoms during 
atropia-poisoning in animals of a higher development, suggested 
the possibility of the tetanic symptoms being caused in frogs by an 
influence originating in the cerebral lobes, or, more probably, in 
the ganglia at the summit of the medulla. Accordingly, on several 
occasions, the cord of a frog in the stage of tetanus was divided 
immediately below the brachial enlargement. After this operation, 
however, the tetanic condition continued in both the anterior and 
posterior segments. Violent tetanus could be readily excited in 
either segment ; and this condition frequently lasted for many days 
after the division of the cord. 
There can, therefore, be no doubt that these tetanic symptoms 
are caused by an action of atropia on the spinal cord. 
4. On Rhabdopleura , a New Genus of Polyzoa. 
By Professor Allman. 
Professor Allman described a new genus of Polyzoa, obtained by 
the Rev. A. M. Norman and Mr J. Gwyn Jeffreys, from deep-sea 
dredgings in Shetland. 
Its coenoecium consists of a branched tube, partly adherent and 
partly free, the free portion forming tubes of egress, through 
which the polypides move in the acts of exsertion and retraction. 
In the walls of the adherent portion a rigid chitinous rod is de- 
