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May 13, 1851. 

 John Edward Gray, Esq., F.R.S., in the Chair. 

 The following papers were read : — 

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



ADDRESSED TO W. SPENCE, Esft., F.R.S. 



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



In a letter with which you fovoured me some weeks ago, yon 

 made mention of Schiodte's ' Faunae Subterrancae 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. 



Reflecting on the subject, I thought it worth while to examine with 

 some care the eyes of the common Mole, an animal that spends the 

 greater portion of its time beneath the surface of the earth, and seems 

 in its general organization specially adapted for a subterraneous life. 



I shall chiefly notice what, in the dissections I have made, appears 

 to be peculiar. 



The first peculiarity that arrests attention is, that the eyes of the 

 Mole are not contained in bony sockets, but lie unprotected by any 

 bony prominences in the cellular tissue, beneath the common integu- 

 ments ; and, in consequence, were this animal an extinct one, and its 

 skeleton found in a fossil state, there being no orbit, the palteontolo- 

 gist might be led to infer that it is a species destitute of eyes. 



The next peculiarity I would mention is in regard to eye-lashes. 

 These too it seems to be destitute of. The hair in which the eyes 

 are buried, and by which they are defended, seems to be the common 

 fur of the head. I could detect in that immediately surrounding 

 them no hairs of larger dimensions, or in any respect different from 

 those of which its fine fur is composed. 



The apertures for the admission of light constitute another pecu- 

 liarity. When the fur is removed from the skin surrounding the 

 eyes, a minute aperture appears over each, about aV*-^^ ^^ ^^ "I'^^i "^ 

 length when closed, and, in this state, linear and straight, but cir- 

 cular when fully expanded. The extreme margins of these openings 

 in the integuments being covered with fur, there is no well-marked 

 appearance of eyelids, — indeed, it may be a question, whether the 

 Mole, in strictness, can be said to possess these appendages. From 

 the observations I have made, I am disposed however to infer that it 

 does possess them, but imperfect ; — imperfect, not having been able 

 to detect beneath the marginal cutis any vestige of ciliary cartilages, 

 and yet haraig found in the surrounding subcutaneous cellular tissue 

 muscular fibres so arranged as if designed for closure, resembling an 

 orbicular muscle, and probably designed for and performing the part 

 of such a muscle. 



No. CCXXVII. — Proceedings of the Zoological Society. 



