^ioumS, iri869^ PROCEEDINGS OF SOCIETIES. 255 
drawn. He did not agree with the statement of the Professor, that 
the characteristic affinities of animals could be distinguished by the 
fineness of the fibres of the Crystalline lens. With regard to the 
classification of animals, the tendency of the present d ij was too much 
to run upon a single character. 
Dr. Lawson made some observations on the remarks of Dr. Murie 
and on Professor Gulliver's paper. 
The President said : — It was a question whether Professor Gulliver 
was correct in stating that the edges of the fibres of the lamprey are 
absolutely smooth. Sir D. Brewster had stated, that when he was 
examining the Crystalline lens, it v/as an unquestionable fact, that in 
fibres of fishes teeth existed to a very great extent; yet he doubted 
the existence of teeth in the edges of the fibres of Mammalia. After- 
wards, however, by means of a better illumination, he was able to see 
the teeth by the aid of the phenomena of polarized light. Professor 
Gulliver has not alluded to these phenomena, and it is probable 
that he may not have seen them. The form of the lens in fishes 
is generally a prolate si)heroid, the fibres converging from the 
Equator to the Poles. The thickness and breadth of the fibres which 
Professor Gulliver has given is probably correct. In the case of 
the cod. Sir D. Brewster gives the breadth of the fibres as the 
6500th part of an inch ; in each fibre there are 12,500 teeth ; in the 
lens there are 5,000,000 fibres; consequently there are 62,500,000,000 
teeth in the fibres of the lens of a cod. Then with respect to the 
action of polarized light, it is very remarkable that in the lens of 
fishes we have the concentric circles of light, separated by two con- 
centric dark circles (the circles being very faint on the outer jjortion 
of the lens), and the whole intorsected by a black cross. Sir D. 
Brewster observed also a remarkable variation of density — the 
concentric circles in the nucleus and the outer portion of the lens 
being negatively polarized, and the intermediate portion being posi- 
tively polarized. In animals, however, the nucleus and the outer 
portion have positive double refraction, while the double refraction of 
the intervening structure is negative — a result exactly contrary to that 
exhibited in fishes. Sir David says, the varying density — that is, the 
increase of density from the surface to the centre of the lens — is 
probably intended to correct s^jiierical observation. Of the other 
properties of the structure Sir David Brewster says, they have not 
even excited the " ingenuity of conjecture." The subject is higlily 
interesting, and there is a wide field open to the Fellows of the Society 
for investigation. 
Mr. Alfred Sanders then read a paper " On the Zoosperms of 
Crustacea." 
A vote of thanks was passed to Mr. Sanders. 
The President announced that the next meeting will take i^lace on 
the 14th April, when papers will be read by Dr Lionel Beale " On 
Protoplasm and Living Matter;" and by Mr. Suffolk " On the Proboscis 
of the Blowfiy," illustrated by the valuable drawing which had been 
submitted to the Fellows. 
The Meeting of the Fellows was adjourned to the 14th April. 
