502 Mr. Bray ley on the ocular points of the Helicidoe^ 



With respect to the first of these classes, it appears io be a 

 matter of great doubt whether they possess even the minute organs, 

 which, in the Gasteropoda^ have usually been regarded as organs 

 of sight. For Cuvier, though he states, in the first instance, that 

 a part only of the Pteropoda are devoid of eyes,* yet, in his parti- 

 cular description of the class, he merely says that some writers have 

 assigned eyes to the animals of the genus C//o,+ and does not again 

 allude to the subject. And Dr. Fleming, in his excellent Philosophy 

 of Zoology, informs us, that the Pteropoda " are generally regarded 

 as destitute of eyes and ears." J Lamarck, indeed, enumerates 

 ^' oculz duo*' among the characters of his genera Cleodora and 

 CymbuUa ; || but from a remark he subsequently makes, and 

 which will presently be quoted, we may fairly infer, I think, that 

 the organs he so denominates are similar to those of the Gastero- 

 podous MoUusca; which I shall next proceed to shew, on the 

 authority of Messrs. Gaspard and Bauer, as well as on that of a 

 modern Zoologist of the first reputation, are to be regarded, in 

 all probability, not as organs of sight, but of delicate touch. 



We see then, that, in the present state of science, the only di- 

 vision of the MoUusca from which any decided instances can be 

 adduced, in opposition to the statement of the Grecian naturalist, 

 of testaceous animals possessing even the organs supposed to be 

 eyes, is the Gasteropoda ; the inquiry being thus confined with- 

 in very narrow limits. 



The minute organs, appearing to the unassisted eye merely as 

 black points, which are possessed by certain groups of the Gas- 

 teropodous MoUusca^ a class including the greater number of the 

 animals that inhabit univalve shells, and which are commonly 

 attached to their tentacula^ have been conjecturally stated by 

 some systematic naturalists to be organs of vision ; whilst others 

 have doubted this, and considered them rather as organs of 

 touch ; but none appear to have subjected the living animals or 

 their supposed eyes, to a strict and decisive examination, with the 

 view to determine the truth. Hence we find in the works even 



♦ R^gne Animal, torn. II. p. 354. + Ibid. p. 379. % Phil, of Zool. 



vol. II. p. 441. 11 Aniin. sans Verteb. torn. VI. p. 289, 293. 



