PKOCEEDINGS OF THE SOCIETY. 333 



Mr. Crisp read a letter received from Dr. Hudson, the President, 

 expressing the regret which he felt at his enforced absence in con- 

 sequence of the effects of the accident to his knee, reported at the previous 

 meeting. 



Mr. Cooke exhibited a number of photomicrographs of the odonto- 

 phores of Mollusca, as an attempt to illustrate this group of objects by- 

 photography. He said that the pbotographs had been made from speci- 

 mens arranged and selected by his friend Mr. Watkins, his own part in 

 the matter being the photography. Mr. Watkins had in his collection 

 about 1400 specimens from which the series had been made. The 

 classification of Mollusca by means of the radula dated back to the 

 work of Prof. Loven, but had not received the recognition which it 

 should, and in his opinion would have in the future. He imagined that 

 this want of attention was largely due to the extremely inadequate 

 representations which had hitherto been made of these organs, for in tho 

 drawings usually made it had generally been the practice to select only 

 one row of teetb, from which it was obvious that only a very imperfect 

 idea could be obtained of the whole. The photographs had the advan- 

 tage of showing considerably more. Then again the figures in most 

 cases omitted the shading, which was a very important part, so that they 

 failed to indicate the thickness. The present series of photographs had 

 been prepared with a very rude apparatus, mainly of his own devising, 

 which when closed folded into a space of 1 ft. 6 in., but could be 

 expanded to 5 ft., thereby enabling him to get increased magnifying 

 power without the necessity for using a large number of lenses. He bad 

 used Swift's 1 in., 1/2 in., and 1/4 in., and one of Zeiss's 1/12 in. im- 

 mersion lenses with a projection eye-piece, giving for the whole a range 

 of powers from 30 to 600. The results already obtained were such that 

 he ventured to think that when that method of illustration became better 

 known and had been further improved upon, the system of classification 

 by the radula would receive better recognition. Amongst instances in 

 which the application of the method had led to valuable results, he 

 mentioned that there had been described as being found in Australia no 

 less than fifty-two species of the genus Physa which ranged generally 

 throughout the South Pacific. Specimens of these having come to hand, 

 proved upon examination to be no Physa at all, but really a sinistral 

 Limnsea, and when they were able to get more specimens, he thought it 

 very likely that they would be able to get rid of the whole of those fifty- 

 two species of so-called Physa. He ventured to ask any Fellows of the 

 Society that could to assist them in procuring new specimens, as he found 

 it a matter of extreme difficulty to obtain shells with the molluscs inside 

 from the remote corners of the earth. 



Prof. Stewart said that he had listened to the remarks of Mr. Cooke 

 with very great pleasure, and was delighted with the series of photo- 

 graphs which had been submitted for their inspection, which he thought 

 were exceedingly well done, considering that in many cases great diffi- 

 culty was encountered in consequence of colour and want of flatness in 

 the object. He should like to ask what was the bearing of the structure 

 on the evidence as to the character of the food — was there anything 

 which would tell them whether the creature was carnivorous or a 

 vegetable feeder ? and if the former, whether it fed upon the softer kinds 

 of flesh, or was capable of boring through hard shell ? In making a 

 1888. 2 A 



