806 



length in the lumbar vertebrae, in the last of which it is also much increased in breadth, espe- 

 cially on the right side, where it presents a rough surface for articulating with the contiguous 

 parts of the sacrum and the iliac bones. The pelvic cavity exhibits the sexual expansion, 

 but the iliac bones are smaller and narrower than in the European female : they are much 

 thinned and the substance is partly absorbed at the centre, indicating the effects of pressure 

 during pregnancy. 



Presented by the Zoological Society of London. 



The following, to No. 5284 inclusive, are parts of the skeleton of a male Australian, from 

 the neighbourhood of Port Essington : 



Presented by Captain Blackwood, E.N. 



5185. The skull. 



A small portion of the alisphenoid joins the parietal on both sides. The right anterior 

 incisor has been removed during life and the alveolus is obh'terated. As compared with the 

 Chimpanzees this skull differs most in the great superior capacity of the cranium, and in the 

 shortness of the jaws, especially of the upper one. The outer surface of the nasal bones is 

 arched transversely. The foramen magnum is placed nearer the centre of the base of the 

 skull, the anterior end of the condyles reaching the transverse line which equally bisects the 

 base. The condyles are relatively larger. The mastoids are developed into processes of the 

 size and form which gave rise to the name. The stylohyals are anchylosed, and are sup- 

 ported anteriorly by a ridge from the tympanic called the ' vaginal process.' The eustachian 

 process of the petrosal is shorter. A short styliform process is developed from the lower and 

 outer angle of the alisphenoid. The glenoid cavity for the mandibular condyle is deeper, and 

 is formed behind by the tympanic. There is also a low postglenoid prominence. The bony 

 palate is much shorter, but is proportionally deeper and broader than in the Chimpanzees, 

 and the teeth are arranged in a full semielliptic contour without any natural interspace, the 

 crowns being of equal length. The incisors, premolars, and, above all, the canines are rela- 

 tively smaller as compared with the true molars. The zygomata are shorter, thicker, and 

 more arched upwards. The interorbital space is wider, the superorbital ridge is much less 

 prominent, and the whole circumference of the orbits deviates more from the circular figure. 

 The upper border of the squamosal describes a convex curve. The symphysis of the lower 

 jaw is deeper and has a prominent inferior border or chin. The premolars have only one 

 external fang, instead of two, as in the Chimpanzees. 



5186. The atlas. 



There is a tubercle from the hypapophysis representing the body, and a rough surface on 

 the neural arch in place of a spine. The vertebral artery perforates the transverse process 

 lengthwise, and afterwards grooves the neural arch behind the produced angles of the ante- 

 rior zygapophysis. The body is longer and deeper in proportion to its breadth than in the 

 Chimpanzee. The surface for the odontoid is more nearly circular and better defined. The 

 cavities for the condyles are relatively larger, deeper, with their margins more produced. 

 The pleurapophysial boundary of the vertebral arterial foramen is much thicker than the di- 



