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Show 1886.] MAMMALS IN THE SOCIETY'S GARDENS. 215 atlas had become firmly ankylosed to the occiput, and it is very curious that the animal could have survived so serious an accident. A somewhat similar case came under observation in an Ichneumon. In this instance tbe atlas had been dislocated from its relations to the occiput and axis, so as to occupy the situation shown in the accompanying drawing (fig. 7). In this instance the animal must have survived the injury a long time, because the occiput and atlas are firmly united by new bone. Concretions formed of insoluble or indigestible matters are of frequent occurrence in the alimentary canal of Horses and Cattle, and at times may attain to very large size without causing any inconvenience. This is more particularly the case when these segropiles, as they are termed, occur in the caecum of horses. In this situation they bave been known to weigh more than fifty pounds. These heavier masses are composed of magnesium phosphates ; the lighter ones consist of hair which the animal licks from its body. This form is fairly frequent in calves, and I have met with a specimen in a Hysena. Concretions of insoluble substances, such as magnesia, pins, seeds, & c , occur also in the human subject. Recently a Tiger died in the Gardens, and its bowels were found empty until the rectum was reached. Here a large mass of solid material was found about two inches from the anus, measuring six inches in length and eight inches in girth, covered with mucus. The lower end was bluntly pointed, and had caused by its pressure ulceration of the mucous membrane. The rectum was much dilated. On breaking into the mass it was found to be composed entirely of sawdust, which the animal had licked from the floor of the cage. A cast of the abnormal mass was taken at the time by the assistant, Mr. Ockenden. During tbe past four or five years there is one fact more than any other which has impressed m e in the course of m y work at the Gardens, and that is the infrequency of neoplasms. In the many hundreds of animals coming under observation, a tumour has been a rarity, and this applies with still greater force to cancers. The only example of this terrible malady I have seen in ivild animals was a medullary cancer in the viscera of a Python. The infrequency of these growths makes the following case additionally interesting. A Short-headed Phalanger, Belideus breviceps, was found to have a large, hard nodular mass in its marsupium. On slitting open the pouch a tumour presented itself, having the appearance represented in fig. 8, p. 216. Microscopically it presented all the characters peculiar to scirrhous cancer as seen in the human subject-that is, there were alveolar spaces enclosing masses of cells. The alveolar walls were composed of dense fibrous tissue. The structural details of the growth coincided with that of the gland from which it originated, except that the cells, instead of clothing the walls of the alveoli in a regular manner, were tumbled in confusion into the interior. This case is, so far as I know, the first authentic example of cancer in a marsupial. The last specimen on my list is perhaps as interesting as any. It is an intussusception of the ileum into the caecum, through, but not |