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Show 716 MR. W. SAVILLE KENT ON THE [Nov. 19, Concerning the erect bipedal method of perambulation of Chlamydosaurus, it is worthy of remark that during such progress the fore limbs hang lax and motionless, while the long, slender tail is elevated quite clear of the ground, and, swaying slightly from side to side, plays apparently an important part in preserving the animal's equilibriuml. By experimentally tethering examples of this Lizard to light cords in such a manner that they possessed full freedom of action, I ascertained that they will run for a distance of at least thirty or forty feet at a stretch without touching the ground with their fore feet, and then, after resting momentarily on all fours, will make a new start in the erect position, and thus continue running and resting alternatively for a period of some minutes' duration. Although no other existing species of lizard is known to possess a similar faculty of perambulating upon its two hinder limbs, it is perhaps worthy of record that I have often observed of Australian species of Grammitophora that when running they carry their heads erect in the air, at the same time sitting up, as it were, on their haunches, and with the whole anterior portion of their bodies raised to the greatest possible height by the full extension of their anterior limbs. A similar semi-erect or " sitting-up" position is also, I may observe, usually assumed by the Frilled Lizard, Chlamydosaurus, when resting on the ground (see Fig. 2, p. 717), and when running for so short a distance only as two or three yards. The progress of Chlamydosaurus in its most characteristic bipedal fashion is tolerably rapid, insomuch so that it was found impossible to obtain a distinct photographic picture of a specimen under such conditions at a distance of four or five yards with a Kodak camera having its shutter working at a speed of the y-^th part of a second, and it was only by enlisting the aid of an Anschutz camera with a shutter set at the speed of the -g-jj^th part of a second that the results here reproduced were secured. Even under these more favourable conditions I was unable to obtain as clearly defined a profile representative of the running lizard as might be desired. Among those secured, however, there is one (submitted) remarkable for the resemblance that the contours of the semi-erect body and 1 Since the setting-up in type of this paper I am indebted to the Secretary for a previous reference to the reported bipedal comportment of Chlamydosaurus. This is made by Dr. Henry Woodward in vol. xxx. p. 13 of the Quarterly Journal of the Geological Society, 1874. By a happy coincidence that accomplished geologist, in company with Dr. Giinther, overheard the comments of an Australian visitor to the British Museum on a stuffed specimen in the collections, and they were informed that this species habitually ran on its hind legs. Dr. Woodward utilizes this and collateral evidence presented extensively in his paper here quoted, which is an amplification of Prof. Huxley's essay on " Animals intermediate between Birds and Reptiles " (' Popular Science Review,' 1866), and bears practically the same title. Dr. Woodward's concluding paragraph, to the effect that " the bipedal habit of the Secondary Reptiles is a peculiarity still maintained by the Australian Chlamydosaurus," is of special interest with reference to the latter portion of this paper. |
