On the means by ickicli Animals walk on polished Surfaces. 115 



zag band of black at about half their length from the base, then 

 greenish blue to the tip, the inner webs fading into white near 

 the extreuiity ; throat and chest yellowish emerald-green, each 

 feather ti])ped with verditer-blue ; middle of the breast and the 

 sides vcrditer-blue; abdomen and under tail-coverts scarlet ; irides 

 dark brown ; bill horn-colour, becoming blackish gray at the base ; 

 legs and feet yellowish brown. 



Length about 12 inches ; bill i ; wing i)\ ; tail 7^ ; tarsi ^. 



Nearly allied to Plati/cercus hannatogaster. In habits it is a 

 truly grass-feeding parrakeet. 



For this beautiful species I propose the name of Platycercus 

 pulcherrimtis, 



And remaiuj dear Sir, yours truly, 



To R. Taylor, Esq. John Gould. 



XVIII. — On the Means hy luhich various Animals walk on the Ver- 

 tical Surfaces of hiijhly polished Bodies. By John Blackwall, 

 F.L.S. 



Perceiving among eminent naturalists and jdiysiologists in this 

 country not only a disinclination to adopt the explanation of the 

 means by which animals of various species ascend the vertical 

 surfaces of highly polished bodies, published in the '■ Transactions 

 of the Linn^ean Society,' vol. xvi. pp. 487, 1^1 , bnt also a dis- 

 position to adhere to the old and exploded view of the subject, 

 which has been recently introduced into important works on zoo- 

 logy and physico-theology, in the course of last antumn I made 

 several experiments bearing directly upon the remarkable phse- 

 nomcnon imder consideration, the particulars of which I shall 

 proceed to state. 



Having captured vigorous specimens of the following insects 

 and spiders, Coccinella vigintiduo-jmnctata ; the common earwig, 

 Forjicula auricularia ; the hive-bee. Apis mellifica ; the common 

 wasp, Vespa vulgaris ; the house-fly, Musca domestica ; the large 

 flesh-fly, Musca vomit aria, Philodromus dispar, and Drassus seri- 

 ceus; and having ascertained that they could walk with facility 

 upon the ])erpendicular sides of a well-cleaned glass-jar, I put 

 into a perfectly dry and clean phial a sufficient quantity of nitrate 

 of silver in a very finely pulverized state to cover the bottom of 

 it to the depth of about one-twelfth of an inch ; then holding the 

 phial at various degrees of inclination to the plane of the horizon 

 and turning it roimd, I distributed in this manner many of the 

 finer particles of the caustic over the whole of its inner surface. 

 Into the phial thus prepared I introduced, in succession, the in- 

 sects and spiders named above, taking care to renew the nitrate 



