500 Mr. Brayley on the ocular points of the Helicidce^ 



rising through it, and expanding into the quinquefid pellucid ter- 

 mination, which he supposed to be the cornea. 



The consideration of this curious subject brought to my 

 recollection a passage I had read in some old author, in which 

 Aristotle is said to affirm, that '•' Testaceous animals have no 

 eyes ;" and the accuracy which several modern Naturalists of the 

 highest eminence have shewn many of that philosopher's generali- 

 zations to possess, seemed to render the statement worthy of 

 verification and further inquiry. And upon referring accordingly 

 to his History of Animals, I found the following notices on the 

 point in question. 



In Lib. I. cap. ix., where the Eyes are treated of in general, 

 as they exist in man and in the lower animals, the Stagirite asserts 

 that all animals have eyes, with the exception of the Testacea, and 

 some other imperfect kind, and perhaps also of the Mole. " Ha- 

 bent profecto oculos, turn caetera animalium genera omnia, prae- 

 terquam testa intecta (Offaxo^ef^a), et si quid imperfectum aliud 

 est:"&c.* 



In Lib. IV. cap. i. the Of§x>co^s^(Ax are identified with the true 

 Testaceous Mollusca, and accurately distinguished from the 

 Cephalopoda on the one hand and the Crustacea on the other, 

 in the following manner : '' Nunc ordinem animalium, quae san- 

 guine carent, persequemur. Genera in hoc ordine plura sunt. 

 Primum, quae moUia (MxXuycix) appellavimus, hoc est quae san- 

 guine carent, et foris carue molli obducta, solidum intus, modo 

 sanguinei generis continent : quale sepia est. Secundum, quae 

 crustis tenuibus (MaAaxoo-Tfajca) operiuntur, hoc est, quse partem 

 solidam foris, mollem carnosamque intus continent. Durum illud 

 eorum tegmen, non fragile, sed coUisile est : quale cancrorum 

 genus et locustarum. Tertium, quae silicea testa conclusa 

 (OrfaxoJe^/xa) muniuntur, hoc est quibus pars carnea intus, solida 

 foris, fragilis atque ruptilis, non collisilis : quale genus concha- 

 rum & ostrearum est."+ 



* Aristotelis Opera Omnia. Gr. & Lat. cura Da Val. Tom. I. p. 769. 

 • Lutet. 1619. Fol. 

 f Ibid. p. 813. 





