MUSEUM OF COMPARATIVE ZOOLOGY. 15 
On the whole, it appears that the eye of Proteus is more rudimentary 
than that of either Typhlogobius or Talpa. The most distinct indica- 
tion of this is in the absence of the lens in the adult animal. 
With reference to it Schlampp says (’92, p. 555): ‘ Die Linse [in Pro- 
teus] wird gleichzeitig mit der Kinstiilpung der primaren Augenblase 
angelegt, wichst in den sekundaren Augenbecher hinein, wo sie bei der 
Larve noch in der Gegend des vorderen Angenpoles zu finden ist. Sie 
kommt aber iiber die zellige Struktur der embryonalen Linse nicht 
hinaus, erleidet vielmehr durch Nichtgebrauch alsbald eine Riickbil- 
dung, so dass sie bei ganz jungen Thieren an Groésse und Zellmasse 
schon bedeutend reducirt ist, im spateren Leben aber resorbirt wird und 
spurlos verschwindet.” 
The lens is present in Talpa, though it retains its embryonic cellular 
structure throughout life, wholly according to Hess (’89, p. 8), partly 
at least according to Kohl (’89, p. 385) and others. In this regard, then, 
it is more rudimentary than the lens of Typhlogobius. The choroid 
is present in Proteus, consisting, according to Kohl] (’89, p. 406) “aus 
mehreren Zellenlagen mit reichlichem Pigment, das sich stets in zwei 
Lagen anordnet, von denen bald die eine, bald die andere die gréssere 
Starke besitzt. Die innere derselben reprisentirt das vielfach (so auch 
Hess) schon zur Retina gerechnete Pigmentepithel.” It also contains 
blood capillaries according to both Kohl and Hess. As regards the 
choroid and the pigment lamella of the retina, it would seem, according 
to these statements, that the eye of Typhlogobius, with its exceedingly 
rudimentary choroid and greatly thickened pigment lamella, is some- 
what more rudimentary — it may be even degenerate —than that of 
Proteus ; though it must be borne in mind that the choroid is compara- 
tively feebly developed in normal teleostean eyes. 
In Talpa the choroid reaches a relatively slight development, and has 
little pigment, while the pigment layer of the retina is highly developed 
(Hess, ’89, pp. 3 and 4). In this regard it more nearly agrees with 
Typhlogobius than does Proteus. The iris, considerably thickened with 
pigment, the ligamentum pectinatum, ciliary body, and ciliary muscle, are 
all present, though reduced, in Talpa, according to Hess. 
With regard to the retina of Proteus, Schlampp’s statement in his 
summary is as follows: “ Die Retina breitet sich, Mangels des central 
Glaskorperraumes, nicht fliichenhaft aus, sondern wird eine solide 
Kugel, welche axial von Sehnerven durchzogen wird. In ihrem histolo- 
gischen Baue weicht sie nicht wesentlich von der Netzhaut der Am- 
phibien ab, die Endapparate erreichen aber die endgiiltige Form nicht.” 
