282 FUNCTIONS AND INSTINCTS. 



bably that their motions might not be impeded 

 by any roughness of their shell. 



Mr. E. W. Brayley, in a very ingenious me- 

 moir, in the Zoological Journal, has contended, 

 with considerable strength of argument, that the 

 moveable black points, in the upper tentacles of 

 snails, though he allows they may be their ana- 

 logues, are not real eyes ; but the Rev. L. Guild- 

 ing, in a subsequent part of the same Journal 

 states, that the large strombs of the Caribbean 

 sea have eyes furnished with iris and pupil, 

 similar to those of birds and reptiles that they 

 have also a vitreous and aqueous humour, and 

 a black pigment, which certainly prove them 

 to be real eyes their organ of hearing, he 

 thought, was likewise distinct. The cowries also 

 are said to have eyes exhibiting both iris and 

 pupil, as have some volutes. 1 



Giving these facts their due weight, I think 

 we may conclude that the, so called, eyes of 

 snails, are real though imperfect visual organs. 

 It appears to be the plan of the Creator, 



to ascend 



From small beginnings to a glorious end. 



An organ is, as it were, sketched out, in the lowest 

 animal, as for instance, a nervous system, which 

 keeps developing and improving till it is brought 

 to its acme in the highest : first we find in the 



1 Valuta ethiopica, PLATE VI. FIG. 1. a. 



