in support of an assertion of Aristotle* 503 



of comparative anatomists, and of those naturalists who are most 

 conversant with the anatomy and physiology of the MoUusca^ but 

 very imperfect and vague information on the subject. Thus Dr. 

 Fyfe, in his Outlines of Comparative Anatomy, p. 312, remarks, 

 when describing the organs in question, '' it is not yet fully 

 ascertaiaed whether these parts are real organs of vision." Cuvier 

 seems to take it for granted they are eyes, without offering any 

 evidence to verify that admission ; * and Lamarck does the same, 

 but he qualifies the statement, by observing, after mentioning the 

 conformity of the eyes of the Cephalopoda to those of the Verte- 

 brated animals, '^ les autres moUusques, parmi ceux qui en sont 

 munis [d'yeux], ont les leurs fort imparfaits, peu propres a 

 I'asage de la vue, et presque uniquement tentaculaires, c'est-a-p 

 dire, plus sensibles ou irritables au contact des corps concrets 

 qu'a celui de la lumiere."+ Dr. Fleming gives the following ac- 

 count of the subject : " Among the Gasteropodous Mollusca^ the 

 eye is too minute to admit of accurate dissection. It appears as 

 a black spot, convex, however, on the surface, and furnished with 

 a nerve from the cerebral portion of the brain." Phil, ofZooL 

 vol. I. p. 181. — " In a few species [of MoUusca'] the eye is con- 

 structed on the plan of the same organ in the vertebral animals, 

 In general, however, it appears only as a black point, the peculiar 

 functions of which can only be inferred from analogy." Ib» vol. II. 

 p. 409. 



Mr. W. S. Macleay, indeed, as might have been expected, from 

 the importance he assigns to variation of characters, in determin- 

 ing the station in nature of a group of organized beings, as well as 

 to the adaptation of their structure to their respective functions in 

 creation, assumes a more decided tone of opinion on the subject. 

 When alluding to the senses of the MoUusca, in the chapter on 

 the classes of the animal kingdom, in his Horce EntomologtccBy 

 p. 248, he observes, " The senses of the MoUusca seem to be 

 confined solely to those of taste and touch, though Cuvier sup- 

 poses them to be also able to smell. The black points which 

 have attained the name of eyes, seem to serve less for sight than 



* Regne Animal, torn. II. p. 382. 



+ Anim. saus Verteb. torn. VI. p. 272. 



