240 Miscellaneous. 



by a great number of cavities, which may be compared with those 

 of a thimble. Each of these depressions is lined by the characteristic 

 pigment, and also connected at the bottom with the nervous ganglion, 

 which occupies the centre of the papilla, and, as it were, forms its 

 nucleus. The depressions are filled with a very transparent gelati- 

 nous matter, forming a slight projection at the surface of the oculi- 

 ferous tubercle, and terminated by a convex portion, like the cornea 

 of the higher animals. By the action of glycerine, this refractive 

 •matter swells up, and the projection just mentioned becomes more 

 marked. 



From the description that we have just given of it, some physio- 

 logists will no doubt be led to refer the visual organ of Aster acanthion 

 to the great division of idoscopic eyes. But, notwithstanding the 

 presence of a refractive body, which militates in favour of this assi- 

 milation, we shall regard this organ as a photoscopic eve. As in 

 these, the pigment-cells cover the nervous element, and constitute 

 the screen upon which the luminous rays impinge. What, then, may 

 be the function of the refractive substance analogous to the vitreous 

 humour that fills the capsule of the eye ? It will serve to collect 

 and concentrate the luminous rays upon the impressionable pigment, 

 and consequently to render the perception of light, and of its different 

 degrees, more intense and perfect. 



Thus we find in the Aster acanthion a specialization of functions 

 which no doubt represents the highest type of organization of photo- 

 scopic eyes, and a new example of those tendencies which nature 

 appears to obey in perfectioning organs — tendencies from which 

 an eminent physiologist of our day has drawn such brilliant deduc- 

 tions. — Comptes Rendus, January 16, 1865, p. 103. 



Notice of a new Variety q/"Rhodona punctata from the Swan River. 

 By Dr. J. E. Gray, F.R.S., &c. 



Mr. Edward Gerrard has brought to me a Lizard from the Swan 

 River, which differs considerably from the common form of Rho- 

 dona punctata *, indeed so much so that I was at first inclined to re- 

 gard it as a new species of that interesting genus ; but on reconsider- 

 ation, as it only differs in the distribution of the colours, I think that 

 it is better to regard it as a variety. It may be named after its dis- 

 coverer, Rhodona punctata, var. Gerrardii. The body white, with 

 three broad black streaks, which are continued from the head to 

 rather beyond the base of the tail ; each of the streaks is as wide as, 

 or rather wider than, two-thirds of two series of scales. The two 

 outer streaks commence on the side of the nose, and are continued 

 across and along the eye and down the side of the body ; the central 

 vertebral streak commences at the back of the head. The three 

 streaks are continued on the tail ; but they become wider, and are 

 broken up into spots, which have some more or less distinct white 

 streaks across them. The upper surface of the hind thighs is black- 

 spotted, the spots forming a kind of streak ; the chin, belly, and 

 under part of the tail are white. 



Hab. Swan River. — Proc. Zool. Soc. June 28, 1864. 

 * Cat. of Lizards in B. M. (1845), p. 89. 



