July 22, 1897] 



NATURE 



271 



phonetic nomenclature. Thirty-six vowel sounds are 

 developed by labial modifications of sounds produced 

 with definite positions of the tongue and certain size of 

 the cavity of the mouth. The cause of the differences 

 between vowels and consonants is explained, and the 

 mechanism of distinct utterance is expounded. Teachers 

 of languages and elocution may find the book of service 

 for instructing their pupils how to arrange the tongue 

 and lips in order to speak with correct accent. 



LETTERS TO THE EDITOR. 



\The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents Neither can he undertake 

 to return, or to correspond with the writers of rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.^ 



Bipedal Locomotion among Existing Reptiles. 



I COMMUNICATED to NATURE of February 27, 1896, and 

 elsewhere, details with accompanying figures concerning the 

 bipedal locomotion of the North Australian Frilled Lizard 

 Chlamydosaurus Kingi, and which, with reference to such method 

 of progression, apparently occupied a unique position among exist- 

 ing reptilia. As the result of a more recent investigation, I have 

 •discovered that a corresponding bipedal gait is assumed under 

 favourable conditions — i.e. when running across a wide expanse 

 •of smooth and level ground — by the handsome Australian water 

 lizard, Physigitathus Lesseuri, such method of progress being 

 most conspicuously manifested by the young and slender 

 individuals. I have also ascertained that a similar mode of 

 locomotion is adopted under like conditions by Amphibolurus 

 timricatus, and I am inclined to anticipate that it will be found to 

 ■obtain among many other of the Australian, and possibly African, 

 Agamoid lizards that share with the foregoing species a relatively 

 "excessive development of the hinder limbs. 



A like bipedal formula of locomotion has been hinted at, 

 though not yet demonstrated, in the case of the Mexican Iguanoid, 

 Corythophaiies Hernandesyi, and will possibly be found to be 

 shared by many allied members 0/ the same family that present 

 in common with it a corresponding superficial structural paral- 

 lelism with the typical Australian Agamidte. The discovery here 

 recorded is submitted with the main object of indicating that 

 the bipedal locomotion of Chlamydosaurus can no longer be 

 xegarded as a mere specific idiosyncrasy. The fact of its being 

 shared by other widely differing members of the same Agamoid 

 group, together with the circumstance of, as in the case of 

 Physignathus, its being most prominently manifested in young 

 individuals, would appear to indicate that the habit has been in- 

 herited from a race that possessed yet more essentially bipedal 

 progressing proclivities. Reserving fuller details for a future 

 communication. W. SavilLe-Kent. 



Wallington, Surrey, July 18. 



Sensitiveness of the Retina to X-Rays. 



Is it not possible that the persistence of an image on the 

 retina is due to phosphorescence ? This would at once explain 

 the sensitiveness of the retina to X-rays. 



The curious phenomenon of the image moving in the opposite 

 direction, observed by Mr. Harrison (p. 248), is no doubt due to 

 the rays passing through the lens without being refracted ; the 

 effect of the image becoming larger, is also the result of the 

 same cause. All objects to become visible must, therefore, be 

 smaller than the retina. Ernest Braun. 



42 Henslowe Road, East Dulwich. 



Sample-Post for Natural History Specimens. 



In the issue of Nature for June 17 (p. 159) it is stated that, at 

 the recent Postal Congress held at Washington, it was decided 

 that natural history specimens, not sent for commercial purposes, 

 were to be permitted to pass by Sample Post between the 

 countries of the Postal Union. 



Permit me to mention that I have been informed by the 

 Secretary to the Post Office, that the Convention giving effect 

 to that decision does not come into operation until January i, 

 1899. Walter F. H. Blandford. 



July 15. 



NO. 1447, VOL. 56] 



AUSTRALIAN NATURAL HISTORY.^ 



^ITHETHER designed or accidental, it is a fortunate 

 ** circumstance that this sumptuous volume — a real 

 Edition de luxe — makes its appearance at a time when 

 the most remote portions of the British Empire are bemg 

 brought into closer connection with the mother country. 

 At such a time everything that tends to promote a more 

 intimate knowledge of the natural products of our colonial 

 dependencies deserves a hearty welcome at the hands of 

 all interested in the expansion and unification of the 

 greatest empire the world has ever seen. On these 

 grounds, to say nothing of others, Mr. Saville-Kent and 

 his enterprising publishers are to be congratulated on 

 the appearance of the work before us. As an attractive 

 volume for the drawing-room table, it would be hard to 

 equal anywhere ; the beauty of its illustrations, whether 

 in the form of coloured plates or of collotypes, being 

 above praise, and calculated to arrest the attention of 

 many of those who have hitherto cared little or nothing for 

 the products of tropical and subtropical nature. Indeed, 

 the two chromos of coral-reefs at low water, one of which 

 forms the frontispiece, while the other illustrates the 

 chapter on Houtman's Abrolhos, may well make every 

 reader long for the opportunity of beholding scenes of 

 such transcendent loveliness. 



For the production of such a work the author is 

 fortunately gifted with endowments denied to many of 

 his fellow naturalists, for, as we learn from the legends 

 to the chromos, he is not only an accomplished artist 

 with the brush and pencil, but diligent practice has made 

 him no less successful with the camera. And as a con- 

 sequence of this, one of the striking features of the work 

 is a series of life-like portraits of many Australian 

 animals in attitudes as unlike those given in ordinary 

 natural history books as it is possible to conceive ; the 

 one being nature, while the others are but too often 

 death caricatured. What, for instance, can be better than 

 the picture of Spinous Lizards with the curious expan- 

 sions on the neck on p. 84, reproduced on the next page, 

 by the courtesy of the publishers? (Fig. i). It is, how- 

 ever, not only with animate nature that Mr. Kent has 

 been successful, his views of scenery, especially where 

 the wonderful termite mounds are concerned, being 

 admirable works of art, interesting alike to the lover of 

 strange landscapes and to the. naturalist. 



As may be gathered from his preface, the design of 

 the author was not to produce a systematic work on 

 the fauna and flora of Australia— of which we have 

 plenty — but " to present to the English reading public a 

 few glimpses" of its natural products, with special 

 attention to the habits of some of the more interesting 

 animals. In this laudable object he has, on the whole, 

 succeeded admirably ; and although his primary object 

 has not been to attract the professed naturalist, many of 

 his observations — notably those on the use of the leg- 

 spur of the Duckbill— are of the highest importance to all 

 students of natural history. 



Not that Mr. Kent treats many parts of his subjects in 

 a superficial, or even what may be termed a purely 

 popular manner. We have, for example, in the intro- 

 ductory chapter a long dissertation on the relation of 

 Australasia to other countries of the southern hemisphere, 

 which may possibly be above the heads of some of his 

 readers. In this we note that he adopts the view that 

 Australasia, Africa, and South America have been in 

 mutual connection at no very remote epoch ; but in 

 giving his adhesion to the theory that such connection 

 took place solely by means of an Antarctic continent 

 completely cut off from more northern lands, he has 

 evidently not studied some of the more recent literature 

 on this fascinating but difficult subject. And we should 



1 "The Naturalist in Australia." By W. Saville-Kent. 4to. Pp. xv -(- 302. 

 (London : Chapman and Hall, Ltd., 1897.) 



