( 81 ) 
Chemistry. — “On the Enantiotropy of Tin (ID.” By Dr. Ernst 
CoHEN and Dr. C. van Eyk. (Communicated by Prof. H. W. 
Bakuuts RoozeBoom). 
(Will be published in the Proceedings of the next meeting.) 
Chemistry. — “The mixture crystals of Hg Js with Hg Bro.” By 
Prof. H. W. Baxnuis Roozesoom. 
(Will be published in the Proceedings of the next meeting.) 
Chemistry. — “On a new kind of Transition Elements (sixth 
kind).” By Dr. Ernst Conen. (Communicated by Prof. H. W. 
BAKHUIS ROOZEBOOM). 
(Will be published in the Proceedings of the next meeting.) 
Chemistry. — “On Isodialdane.” By Prof. C. A. LoBry pr Bruyn 
and Mr. H. C. Bir. 
(Will be published in the Proceedings of the next meeting). 
Zoology. — Mr. Husrecut presents on behalf of Dr. J. F. van 
BEMMELEN: “The results of a comparative investigation con- 
cerning the patatine-, orbital. and temporal regions of the 
Monotreme-skull’. 
Pes tkalate. 
In both Ornithorhynchus and Echidna the palate has been secon- 
darily prolonged backwards, in consequence of their mode of life, 
and therefore independently of each other, and in two different ways. 
The palatine bones of O. are as broad behind as in front, the 
pterygoids being situated entirely along their lateral borders, quite un- 
connected with the bones forming the wall of the cerebral cavity. 
In the EK. skull on the contrary, the palatines are prolonged 
backwards into slender points, which causes the pterygoids to find 
a place at the roof of the mouth much nearer to the middle line, 
between the oblique postero-exterior border of the palatines and the 
petrosa, thereby allowing them to enter into the formation of the 
cerebral skull-wall. 
The horizontal mouth-plates of the Echidna-palatines are provided 
at their lateral border with two vertical wings: a larger one in front, 
forming the basal part of the wall of the orbital cavity, and a 
