ANATOMY OF THE KANGAROOS. 195 



and radius (the bones of the arm). Moreover, the ulna joints with a cavity in the cuneiform bone 

 of the wrist ; and the first row of wrist bones has three in it, and the second has four. The first 

 phalanges, or those of the thumb, are not placed as a thumb in relation to the wrist bones, and 

 it is the outer fingers that grasp with their claws. As the Kangaroo has to lift up its arm, 

 there is a collar-bone, and the arm bone (hunierus) is perforated on the inner side of the end above the 

 elbow; and the olecranon is long. 



The bladebone has a curved ridge, and the muscles of the upper part are less than those 

 which are attached to the part below it. There are thirteen pairs of ribs to the chest. 



The skull is long and comparatively smooth, and even the ridges for the temporal muscles are 

 only slightly raised ; and in old Kangaroos the bones do not unite or anchylose as they do in the 

 other Mammalia hitherto noticed. The teeth are not used as weapons of offence, but simply to graze 

 with, and the lower jaw is not quite solid at the chin, but only so below, so that the lower incisors 

 can be slightly separated. The ear-bone is remarkable for being separated into three parts, namely, 

 the temporal or squamous, the petrosal, and the tympanic ; and this is rather a reptilian character. 

 Moreover, the air-chambers of the side of the under part of the skull are in the form of rounded 

 prominences, or " bullse." They are situated in the lower part of the ear-bone, called squamosal. 

 The zygoma, or process between the cheek (malar) bone and the ear, is hollow, complete, and arched, 

 its front part being, moreover, extended downwards in a projection which reaches below the grinding 

 teeth, and resembles that of the Sloths somewhat. The lower jaw has its back part, or angle, bent 

 inwards (or inflected) strongly, and this is, except in one set, a characteristic of the Marsupiata. 



The Kangaroo, being a vegetable feeder, lias a stomach suited for the diet, which also permits 

 of a certain amount of regurgitation of food up again into the mouth, when a kind of chewing of the 

 cud occasionally is indulged in. The stomach is large and long, resembling the colon or large intestine 

 of the highest Mammalia in its general shape. It measured, in one instance, according to Owen, no 

 less than three feet six inches, the measurement following its bends or curvatures. It consists of a 

 left, middle, and right or pyloric division. The left ends in two round sacs, and these are really con- 

 tinuations of the stomach sepai-ated to a certain extent by a peculiar arrangement of the three bands 

 of muscular fibres which pass separately along the organ. Numerous clusters of secreting glands are 

 found in the mucous membrane of the stomach in its middle part, and they disappear near the pylorus 

 where the tissues are thick and corrugated. The animal has a small intestine, a caecum, and a large 

 gut, but this last is not much larger than the first part of the stomach. The organs of the 

 circulation of the blood resemble those of the other Mammalia, but there is a distinction which relates 

 to the short period during which the young Kangaroo is a portion of the maternal being. So soon is 

 it born, and so soon therefore must it breathe, that before 

 the heart has grown much, it has the blood from the lungs 

 and the rest of the body running through it. The young 

 Kangaroo breathes when its heart is not fully developed, 

 yet it has the perfect double circulation set up. The 

 auricles of the heart communicate as in other Mammals 

 until birth, but the duration of this communication is very 

 short in the Marsupial, and its traces so evident in the 

 other Mammals are wanting in it. The arteries of the 

 body are simpler than in those Mammals which have a 

 more complicated intestinal arrangement, and Owen, in his 

 great work on the Marsupials, has pointed out that the 

 hind limbs and tail are supplied with arterial blood by 

 vessels which have an arrangement not without its simi- 

 larity to that of birds. Leading a very simple life, and STOMACH OF THE GREAT KANGAROO. 

 one of great sameness, moving in a manner which does () oesophagus; <m) intestine, 

 not require much complexity of muscular action, the nervous system of the Kangaroo could not 

 be expected to be highly organised or fully developed. The brain is small for the body of the animal. 

 It is simple in form, and does not cover the cerebellum, which is visible behind, and has a little lobe 

 on each side. The surface of the brain proper has a few convolutions on it, and more perhaps than 



