1 68 SECTION B. VERTEBRATA. 



experiments, and might be considered a conclusive proof, for the 

 apparent absence of the parasite on microscopical examination did 

 not necessarily show the complete absence of the parasite. Bruce's 

 experience at his experimental station was that although other 

 biting flies were constantly biting the animals, no accidental 

 contaminations occurred, and the reason why the tsetse and no 

 other fly carried the disease was probably on account of the fact 

 that it is viviparous. As the mother fly has to nourish the de- 

 veloping larvae within it, it is necessary for it to feed frequently 

 and often. 



All the evidence that we have in regard to the susceptibility of 

 man is entirely negative. Man is bitten by the fly, and accidental 

 scratches and cuts have been incurred during experimental investi- 

 gation which would have been sufficient to have communicated 

 disease had man been susceptible. 



4. Bipedal Locomotion among existing Lizards. 

 ( With Demonstj-ation.) 



By Mr W. Saville-Kent, F.L.S., F.Z.S., 



Past Preside}! t and Delegate to the Co?tgress of the Royal Society of Queensland. 



Abstract. A bipedal plan of locomotion among existing lizards 

 was first demonstrated by the author in the case of the Queensland 

 and North Australian Frilled lizard, Chlaniydosaurus kingi, brought 

 by him to England in the year 1895. 



A further investigation of the subject by the author has shown 

 that a similar bipedal gait is adopted, under favourable conditions, 

 by other Australian Agamidse, including the large Queensland Water- 

 lizard, PhysignatJms Lcsenri, and the Queensland Tree-lizard, 

 Amphibolurus mui'icatus. It has also been found by the author to 

 obtain, though to a much less marked degree, in the African 

 Agamoid, Againa stellio. 



The facts recorded by the author concerning the bipedal loco- 

 motion of Chlamydosaurus has elicited interesting evidence as to 

 the possession of similar bipedal proclivities by other lizard types. 

 Mr Henry Prestoe, long resident in the West Indies, has attested 

 to the author to having observed it in a large number of West 

 Indian species, chiefly Iguanidae, but most notably in the Diamond- 

 lizard of Trinidad, Aineiva siirinamensis belonging to the Teiidae 

 family. Mr W. F. H. Rosenberg has also testified to the author to 

 having observed small slender-limbed members of the Iguanidae, 

 including the young of the Basilisk, Basiliscns Aniericamis, run 

 erect on their hind legs only along the surface of the water of the 

 rivers of Columbia and Ecuador. 



