156 Journal of Comparative Neurology 



5. Since the latter are homologous with the lateral eyes 

 their derivation is also homologous with the lateral eyes. The 

 differences in structure of the epiphysis need to be explained. 



6. It is highly probable that the enlarged distal end of the 

 epiphysis in Squalus is homologous with the pineal eye in those 

 forms in which it is differentiated. 



In a later article Locy confirms his previous observations 

 and adds that he has been able to trace with certainty the an- 

 terior pair of accessory vesicles into the pineal outgrowth. It 

 thus appears that the pineal outgrowth arises from two pairs of 

 vesicles that are homologous witn those giving rise to the lateral 

 eyes. 



A. Prenant (jo-g^) in addition to historical references to 

 the work ol Duval and Kalt, Leydig, and Carriere, who alone, 

 and independently have found accessory eyes, gives four state- 

 ments as the result of his observations, as follows : 1. The ac- 

 cessory eyes are found in a single species, Angnis fragilis ; 2. 

 They are limited to the embryonic period ; 3. they present in 

 the embryos great variability in their constitution ; 4. they are 

 not constant. 



Rudolf Burckhardt (p-93 and '94) draws the relations in 

 the embryo of Lacerta vivipara 1.3 cm. long, which is here 

 reproduced. 



Fig. 2. 



Ca, Commissura anterior ; cb, Kleinhirn ; cp, commissura posterior ; cs, 

 commissura superior ; D, Shaltstiick ; Ls, Lamina supraneuroporica ; Lt, Lam- 

 ina terminalis ; M, Mittelhirndach ; Mg, Grenze der Mittelhirnbasis ; Np, 

 Nebenscheitelorgan ; 0, Opticus ; P, Paraphysis ; Pa, Ursprung der Plexus 

 hemisphaerium ; Po, Scheitelorgan ; Rb, Rautenhirnbasis ; Rn, Recessus neu- 

 roporicus ; V, velum ; Z, Zirbel ; Zp, Zirbelpolster. 



