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XVII. On the Modifications of the Simple and Compound Eyes of Insects . 
By B. Thompson Lowne, F.B.C.S., Lecturer on Physiology at the Middlesex Hospital 
Medical School, Arris and Gale Lecturer on Anatomy and Physiology 
in the Royal College of Surgeons, &c. 
Communicated by Prof W. H. Flower, F.R.S. 
Received February 27, — Read March 28, 1878. 
[Plates 52-54.] 
Although the compound eyes of the Arthropoda have been examined and described 
with great care in former times by J. Muller,* * * § Leydig,! Gottsche,| and Claparehe,§ 
and more recently by Max Schultze|| and Dr. R. Grenacher,A the improved methods 
and instruments of the present time have enabled me to add considerably to the 
published descriptions of the eyes of insects. 
My attention was first directed to this subject by a paper from the pen of 
Dr. Grenacher. My observations do not accord well with the observations of this 
author, but I think this is chiefly from the fact that he has used the eyes of immature 
insects, which differ greatly from those of the mature insect, and from the difficulty 
there has hitherto been in preparing sections of sufficient thinness to allow the minute 
structure of the pigmented portion of the eye to be observed. I have been enabled 
to overcome this difficulty by imbedding the head of the insect in cocoa butter, in the 
manner first devised by Mr. Schafer, and used by him in the investigation of the 
early conditions of the mammalian ovum ; in this way I have been enabled to obtain 
sections of the requisite thinness. 
In the present communication the principal types of eye are described which I 
have found in the class Insecta. Reserving the distribution of these types in the class 
for a future communication, I shall merely indicate the Orders in which each type is 
found ; and in so doing would especially draw attention to the fact that the number 
of species and genera which I have at present examined is far too small to enable me 
* Yerg. Phy. der Gresichtssinnes, 1826. 
f Mull-er's Archiv., 1855. Lehrbnch der Histologie, 1857. 
% Muller’s Archiv., 1852. 
§ Kol. Zeitsch., band viii. 
|| Archiv., band iii., 1867. 
Zehender Monatsblatt, 1877. 
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