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found that at the bottom of the cup there were the four cells as in the 

 others. He objected to the name, and proposed to call it instead the 

 Hydro-conic eye, because it was found that although a cone existed in the 

 eye of the pupa, its cells afterwards are replaced by fluid. In addition to 

 these there was another form of eye which he believed no one except him- 

 self had pointed out. This form was then minutely explained by reference 

 to a diagram ; the cornea was said to be non -lenticular in shape, and the 

 cone was described as consisting of four spherical bodies attached to deli- 

 cate stems, which, in a modified form, passed down through the cup into the 

 cornea. This structure was said to be found in all diurnal lepidoptera and 

 in most of the grasshoppers. Another form of eye was then described by 

 reference to a diagram, and shown to consist of a lens of very short focus, 

 with a retina coming up close to it, the rods being all of a highly refractive 

 nature, like rods of fine spun glass. Another form — found in Tipulse, 

 Gnats, Bees, and Wasps — had spherical lenses, with a bundle of sixteen 

 rod-like structures, beneath each of which had a curious little bright 

 globule attached to it. He thought it possible that these peculiarities of 

 structure might be of use in perceiving other rays than those which we 

 called light, and that nocturnal insects might be able to see objects by 

 reason of their radiating heat. 



The President said that at that somewhat late hour he would not 

 encourage a long discussion, but would invite a few observations from any 

 gentlemen present who might like to remark upon Mr. Lowne's very 

 interesting communication. 



Mr. Chas. Stewart said it was a long time since he had paid much atten- 

 tion to this subject, but he had listened with exceeding interest to Mr. 

 Lowne's remarks, and hoped to reap considerable benefit from them, as he 

 intended to look into some of these questions during the coming summer. 

 As regarded the eyes of dipterous insects, he might say that instead of 

 there being eight of the fibres he had in every case found the number to be 

 seven. In a great number of them there was to be seen an exceedingly 

 brilliant colouring in the eye itself, which rendered many of them such 

 beautiful objects. Had Mr. Lowne any theory to explain this remarkable 

 kind of tapeturn ? He believed he had found it to be due to a layer which 

 existed between the individual lenses, and he fancied that it might have the 

 same problematic value as the tapeturn lucidum in some of the nocturnal 

 animals. A pupillary orifice in some species had also, he believed, been 

 clearly made out ; some sections of spiders also led him to believe that 

 there was little or no difference between their eyes and those of the in- 

 sectidas. 



Mr. Lowne said with regard to the number of the rods, he had not 

 stated the number as being at all precise. Four was, however, the typical 

 number, but in a great many species seven were doubtless found, and it 

 would be seen 'that they ran into one another and anastomosed in a very 

 curious way. He had no doubt that what Mr. Stewart referred to was a 

 true tapeturn lucidum, and that there was yet a good deal to be made out of 

 it. As regarded spiders he must confess that there were a good many in- 



