Page:Proceedings of the Royal Society of London Vol 1.djvu/381

Rh ral; and it was evident, even from external examination, that there were two spines corresponding to the two heads. These were found to terminate in a double os sacrum, tipped with two ossa coccygis; there were consequently two vertebral canals, independent of each other. The chest in front was nearly as usual, with the common number of ribs on each side; but there were also, in the middle of the back, short bones, which must be considered as ribs connecting the two spines to each other.

The chest was divided by its mediastinum into two cavities. In the right was one lung connected with the right head, and in the left another belonging to the left head, without any mutual commu- nication. On inspecting the vascular system, there were found to be two hearts; that on the left, and corresponding with the male head, was much the larger of the two; but they both had the usual num- ber of auricles, and were inclosed in separate pericardia.

The principal difference in the distribution of their vessels was ob— servable in the veins; as the vena cava superior was wanting on the right side, and the right heart received its blood by the vena cava inferior alone; while that on the left had its principal supply by a large vena cava superior, which brought the blood from the of the right head and right subclavian, as well as from those of its own side. But, on the contrary, the vena cava inferior was com- paratively very small.

With respect to the arteries, the difference was not considerable, as they each sent off their respective aorta and pulmonary artery, and each supplied their respective head by two carotids, and their corresponding arm by one axillary artery; after which the two arches united into one trunk as descending aorta.

Little irregularity was observable in the cavity of the common ah- domen, the stomach of which was connected with an oesophagus from the left head; but in a second abdominal cavity, formed by an ob~ lique position of the diaphragm, there was also a smaller stomach belonging to the right head, with a spleen, pancreas, and omentum; but the duodenum from this stomach soon communicated with that from the left side, and the remainder of the intestinal canal was con- tinued onwards, with little deviation from the natural structure.

The organs of generation were very remarkable, as they distinctly partook of both sexes; for though, in the external parts, the charac- ter of the male was predominant, with two testes in the act of pass- ing into the scrotum, yet, in some respects, certain deviations be- longing to the female were even here apparent; and, upon internal examination, an uterus was discovered imbedded in the posterior part of the bladder, from which Fallopian tubes were given off at each side near its upper part.

The author next examined carefully the distribution of the nerves, and found, in general, extremely little connexion between them, excepting at the semilunar ganglion, which was composed of nerves derived equally from both sides.

Each brain, for instance, gavc origin to an eighth pair of nerves,