Zoological Society. 45 



had again been directed to the peculiarities of the organs of vision 

 in the male sex. He had already shown that these individuals pos- 

 sess only ocelli at the sides of the head as well as on the vertex, but 

 that these structures exist at precisely the same parts of the head as 

 the ocelli and the compound eyes in the female, and consequently 

 that there can be no doubt of their homology. These appearances, 

 however, having led some to question the correctness of this, it be- 

 came necessary, in order to judge aright of their nature, to consider 

 what are the essential conditions of a structure which is specially 

 destined for the appreciation of light. This consists, as already 

 pointed out in Fishes, of a follicle or pit in the tegument of the head, 

 coated with dai'k pigment, and receiving the distal termination of 

 a particular cerebral nerve, conditions which are precisely those of 

 the ocelli, both of the sides of the head and of the vertex, in Antho- 

 phorabia. The various modifications of the eye in insects, with re- 

 gard to the form of the cornea, the depth of the chamber, and the 

 presence of the choroid, and of the lens, with reference to the extent 

 of field, and the focal distance, of vision, were pointed out, and the 

 degree in which they exist in Anthophorabia mentioned, as coinciding 

 with the peculiar habits of the insect. The structures in the male 

 were thus shown, by the presence of cornea, chamber, choroid, and 

 nerve, to be most indisputably organs of sight. The author referred 

 also to the binary origin of the nerve of the middle ocellus of the 

 vertex, as formerly pointed out by him in his paper on Pteronarcys ; 

 to the origin of ocelli in the same way as other dermal tubercles ; 

 and to the imperfect eye-spots in the Scorpionidce being supplied 

 with nervous filaments from the same optic nerve which supplies the 

 recognised organs of vision in those animals. 



May 3, 1853. — R. Brown, Esq., President, in the Chair. 



Read a memoir " On the Vegetation of Buenos Ayres and the 

 neighbouring districts." By Charles James Fox Bunbury, Esq., 

 F.R.S., F.L.S., &c. 



ZOOLOGICAL SOCIETY. 

 May 13, 1851.— John Edward Gray, Esq., F.R.S., in the Chair. 

 The foUowmg papers were read : — 

 1 . Observations on the Eye of the Mole, in a letter 



ADDRESSED TO W. SpENCE, EsQ., F.R.S. 



By John Davy, M.D., F.R.S. 



In a letter with which you favoured me some weeks ago, you 

 made mention of Schiodte's ' Faunae Subterranese Specimen,' and 

 of the interesting discoveries described in it of several species of 

 eyeless animals, the inhabitants of caves into which the sun's rays 

 never penetrate, and where, in utter darkness, visual organs would 

 consequently be useless. 



