400 Cambridge Philosophical Society. 



the cheek), the ears, and three continuous narrow lines along (he 

 middle of the back, blackish brown ; the feet blackish, and the tail 

 cylindrical. He also considered it probable that the Civette de Ma- 

 lacca of Sonnerat, Fo_y. t. 91, the Viverra Malaccensis oi GmeXm, be- 

 longed to this genus, with which it agreed in several particulars of 

 its mode of colouring, although it diflered in having a black streak 

 along the middle line of its belly, a character confined to few among 

 the Mammalia. With respect to the Paradoxurns aureus of M. F. 

 Cuvier, he stated that he was inclined to believe that it really be- 

 longed to the genus on account of its naked soles, but was certainly 

 not, as had been imagined, the young of Par. Ti/pus. 



Preparations were exhibited of the stomach and ccecum of a Ca- 

 promys which had recently died at the Society's Gardens, and Mr. 

 Owen read his Notes of the dissection of the animal, which are given 

 in detail in the Proceedings of the Committee. He commenced by 

 remarking that its external characters agreed with those described 

 by M. Desmarest as existing in his Capromys Foiirnieri ; while its 

 admeasurements, especially those taken from the osseous system, 

 corresponded closely with those given by Mr. Say in the Journal of 

 the Academy of Natural Sciences of Philadelphia, when describing 

 his Isodon pilorides, the species on which the generic characters were 

 first pointed out. He further observed that the affinity of this genus 

 to Cavia, indicated by Mr. Say from the comparison of crania, re- 

 ceived corroboration from various particulars of the anatomy of the 

 animal ; an affinity, he conceived, not to be denied on account of the 

 existence in Capromys of perfect clavicles, and their absence in Ca- 

 via ; for an anatomical character, he observed, is not the less artifi- 

 cial if taken without reference to the rest of the organization. The 

 individual examined was a fully grown male, and measured 1 foot 6 

 inches from the end of the nose to the setting on of the tail, the 

 length of the tail being 7§ inches. 



April 1^. — Lieut. Col. Sykes, having brought before the Com- 

 mittee, at previous meetings, various birds of the Raptorial and hi- 

 sessorial orders, collected by him during his residence in Dukhun, 

 completed on the present evening the exhibition of his collection 

 oi" those orders. 



CAMBRIDGE PHILOSOPHICAL SOCIETY. 



March 19. — A paper was read " On the phaenomena of Newton's 

 rings formed between substances of different refractive powers," by 

 Professor Airy. In a previous communication to the Society, the 

 author had announced as a result of theory not yet verified by ob- 

 servation, that " if a lens of a low-refracting substance were laid on 

 a plate of a high-refracting substance, or vice versa, and if the in- 

 cident light were polarized in the plane perpendicular to the plane 

 of reflection, — then, when the angle of incidence was less than the 

 smaller polarizing angle, Newton's rings would be seen with centre 

 black: when the angle of incidence was equal to that angle, the 

 rings would disappear; when it was between the two polarizing 



