THE society's NOTE-BOOKS. 305 



The eyes should be examined in various lights ; arrange the 

 condenser properly, and the eyes will shine like opals. How is it 

 these eyes are so much more brilliant than those of insects ? 



R. K. CORSER. 



Ditto. — I have not minutely examined the eye of cyclops, but 

 comparing Mr. Corser's slide with my own observations on Diap- 

 tomus Castor, I am certainly inclined to support its triple nature — 

 i.e., I think it consists of three crystalline lenses (not facets, for 

 facets are cuticular structures, whereas the lenses are derived from 

 the epidermis). I think it highly probable that the structure of the 

 eye in Cyclops and Diaptomus is essentially similar to that of 

 Daphnia, differing mainly in the fewness of the lenses. 



A. Hammond. 



Cyclops. — In the new edition of the Micrographic Dictionary, 

 Cyclops is said to have a sino^le central eye ; but Huxley, in his 

 Invertebrata, says there are two simple eyes together within the 

 carapace. Nowhere can I find mention of three ocelli. 



T. GOUGH. 



Ditto. — Carpenter states that " this genus receives its name 

 from possessing only a single eye, or, rather, a single cluster of 

 ocelli. The slide enclosed in this box certainly shows three ocelli, 

 whatever may have been written to the contrary. From Mr. 

 Gough's remarks, it seems that one noted scientific man alleges 

 that this Crustacean has two simple eyes. I wonder what he would 

 say of this slide if it came under his own eye. Gosse, in his 

 Evenings at the Microscope (ist edit., p. 216), states that "the eye 

 of Cyclops is elaborately constructed ; for it consists of a number 

 of (not very large) simple eyes placed beneath a common glassy 

 cornea. Several muscle-bands are attached to this compoutid 

 organ of vision, and are arranged so as to form a cone, of which 

 the eye is the base ; these give the eye a movement of rotation 

 upon its centre, which may be distinctly seen." 



I am inclined to think that previous observers were not so 

 much in error as Mr. Corser seems to imply, but that they were 

 not sufficiently precise. They noted that the eye of the creature 

 was situated /;/ a single spot — hence the allusion to the fabled 

 monsters of classic history. More modern observers, as quoted 



