95 



60 Drawings of Hepaticce in portfolio ... ,, Dr. M. C. Cooke. 



A Solar Microscope, by Adams ... ... „ Mr. M. J. Hallett. 



1 Slide, Cheyletus fiabellifer ... ... „ Mr. Michael. 



1 Photograph for the Album „ Mr. M. J. Hallett. 



The thanks of the Club were unanimously voted to the donors. 

 A paper by Mr. Geo. Williams, " On an Apparatus for Facilitating the 

 Use of Powell's Small Bull's-eye Illuminator for the Examination of Test 

 Objects," was read by Mr. Curties (in the unavoidable absence of the 

 author through indisposition). The subject was illustrated by diagrams, 

 and by the exhibition of the apparatus in the room. 



Mr. B. T. Lowne gave an interesting resume of some of his recent 

 researches on the structure of the eyes of insects, which had been lately 

 made the subject of a communication to the Royal Society. Mr. Lowne 

 commenced his remarks by observing that the eyes of insects were not 

 only very pretty objects, but they were also objects of great interest, inas- 

 much as they appeared to have a very different manner of subserving 

 vision from that of the eyes of ordinary Vertebrates. The most probable 

 explanation of the manner in which vision is effected by the insect's eye 

 was that given by Johannes Muller many years ago, and which had since 

 been thought to have been entirely disproved by the production of the 

 multiplied images of objects seen through the eyes in the manner which 

 had been often shown in that room. He believed, however, that he should 

 be able to show that in nine cases out of ten Johannes Muller's view was 

 correct, and that many insects had no lenses at all in the cornea. Attention 

 was next called to the work of Dr. Grenacher on this subject, and to the 

 distinctive forms of insects' eyes which he had described. In his typical 

 or conic eye there was found first a cornea, which might or might not be 

 lenticular ; then a body called the cone, consisting of eight distinct cells 

 and formed of a glass-like structure of great transparency, from which 

 proceeded some extremely fine fibres not exceeding the 30505 of an inch in 

 diameter. These fibres could be traced down into the retina, and they 

 appeared to be formed of some semi-fluid material, seeing that when broken 

 they ran up into viscid drops. Below the cone was a rod-like body which 

 went down into the retina. Grenacher's next form was what he called the 

 Pseudo-conic eye, and which was the kind found in the fly. This consisted 

 of a lens, a cup containing a fluid resembling water, then a remarkable body 

 consisting of four cells, and lastly a kind of rod connecting it with the 

 retina. In addition to these he also found a third kind which he called the 

 a-conic eye, and considered to be a rudimentary form, and one which pro- 

 bably remained so. Mr. Lowne then proceeded to examine these forms as 

 described by Grenacher, and considered that there could be no doubt as to 

 the existence of the conic eye. The Pseudo-conic form was that kind 

 which used to be brought forward in opposition to Johannes Muller's view, 

 and he had himself held to the same opinion at the time when he wrote his 

 work on the Blow-fly. Since then, however, with improved means of 

 investigation at his command, he had so far modified his opinion as to 

 doubt whether it really differed much from the eyes of other insects, for he 



