Kept 1 
REPTILIA AND BATRACHIA. 
BY 
G. A. Boulenger. 
GPJNERAL. 
The discovery of a “ third eye,” or “ parietal eye,” in certain Reptilia 
has been the most startling event in zoological science during the year 
1886. Hereafter follows an enumeration of the contributions on this 
subject. To De Graaf is due the merit of having first clearly shown that 
(in Anguis fragilis ) the pineal gland is modified into a structure compar- 
able to an Invertebrate eye. To Spencer we are indebted for a more 
exhaustive investigation of the matter ; the parietal eye he has shown to 
be more or less developed in a large number of Lizards and in Hatteria ; 
and the parietal foramen of the Plesiosaurians, Ichthyosaurians, and 
Stegocephalians leaves no doubt that the organ was highly developed in 
those extinct forms. The suggestion of Ahlborn and of Rabl-Riickhard, 
that the pineal gland is the remnant of an orgau of special sense in some 
primitive types, is thus confirmed. 
Graaf, H. de. Zur Anatomie und Entwicklung der Epiphyse bei 
Amphibien und Reptilien. Zool. Anz. ix, pp. 191-194. 
Spencer, W. B. The Parietal Eye of Hatteria. Nature, xxxiv, pp. 
33-35, figs. 
Graaf, H. de. Bijdrage tot de Kennis van den Bouw en die Ontwik- 
keling der Epiphyse bij Amphibien en Reptilien. Leyden : 1886, 4to, 
61pp., 4 pis. 
Spencer, W. B. On the Presence and Structure of the Pineal Eye in 
Lacertilia. Q. J. Micr. Sci. xxvii, pp. 165-238, pis. xiv-xx. 
Rabl-Ruckhard, H. Zur Deutung der Zirbeldriise (Epiphysis). Zool. 
Anz. ix, pp. 405-407. 
The author remarks that as early as 1882 \_ef. Zool. Rec. xix, Pisces , 
p. 11], and again in 1884 \cf. op. cit. xxi, Pisces , p. 15], he has arrived at 
the conclusion “ that the glandula pinealis of Vertebrates is to be 
regarded as a rudimentary eye.” 
1886 . [vol. xxnr.] 
c 
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