322 PROCEEDINGS OF THE SOCIETY. 



of this model was that the draw-tube was made to slide outside the other 

 tube, and not inside as in more modern forms ; and by moving it the 

 distance was altered between the field lens and the eye lens. As to the 

 Stuart Microscope, Charles I. died in 1649, so that, of course, if the date 

 assigned to the Homberg Microscope was correct, it was not made 

 before 1686, and therefore not until nearly forty years later than 

 Charles I. It was mentioned by Ciampini as being recently invented, 

 and therefore, though it might have belonged to Charles II., or possibly 

 to James II., and on that account might be called a " Stuart " Microscope, 

 it could not have belonged to Charles I., as stated in the Exhibition 

 Catalogue. 



The President said they were much indebted to Mr. Mayall for his 

 very interesting account of this curious old Microscope. 



Mr. Deby read his paper " On a new Dipterous insect Psamathiomya 

 pedinata " (supra, p. 180), the subject being illustrated by drawings, 

 and by slides shown under the Microscope. Mr. Deby also presented 

 to the Society a set of slides illustrative of the subject of the paper. 



Professor Stewart thought the peculiar form of the foot in this insect 

 was very well adapted for walking upon damp seaweed, keeping it free 

 from any chance of a sucking action. There was a certain resemblance 

 to what was found in the foot of the spider, where the comb-like structure 

 admirably fitted it for running upon the web ; and it was very likely 

 that in the case of this insect it would save it from entanglement in 

 the fine filaments of the seaweeds over which it passed. 



The President hoped some enthusiastic member might go over 

 to Ostend, and would make a search for the insect mentioned by 

 Mr. Deby. 



Mr. Crisp exhibited, on behalf of Mr. T. B. Eosseter, of Canterbury, 

 some slides illustrative of his observations on the presence of Cysti- 

 cercoids in the body-cavity of Cypris. 



Prof. Bell said that he was afraid Mr. Eosseter, notwithstanding his 

 laborious and painstaking observations, did not give sufficiently detailed 

 information to enable a clear opinion to be formed on the subject. He 

 thought the objects were the encysted parasites of some species of tape- 

 worm, and in this surmise he was probably correct ; it was also, he 

 believed, a fact that no observer had yet put on record the discovery of 

 parasites of a cestoid character in the Cypridae. But it was well known 

 that the encysted stage was not the most important part of the life- 

 history of these creatures, and the life-history required to be worked out 

 thoroughly. In tracing out the history of these parasites it was absolutely 

 necessary to find in what creatures their various stages were passed, and 

 to select some for experiment which might probably turn out to be the 

 next host. If, therefore, the duck or the goose were taken, there might 

 have been some probability of finding the next stage. 



The President said that at the last meeting he mentioned the fact 

 of some Eotifera having been found in Australia almost at the same 

 time as in this country. Curiously enough the next night he heard 

 that Mr. Gunston Thorpe had found Trochosphsera in great abundance 

 at Brisbane, and as they had found it there he hoped it might be 

 found here also. It was a rather remarkable form, being perfectly 



