EYE OF NOTORYCTES TYPHLOPS. 549 



tens, in which it is thicker [6, p. 75], and Siphonops [6, 

 p. 105] and Typhlops [6, p. 117], in which it is thinner. 

 From the exterior, therefore, even after shaving off the hair 

 (contrast Scalops [8, p. 335] and Talpa [6^, p. 13]), tJiere is 

 no sign whereby the presence of an eye may be detected 

 (compare Myxine [6, p. 49], Troglichthys rosfe [1, p. 578], 

 Amblyopsis [1, p, 560], Typhlichthys [1, p. 570], and 

 Rhineura [4, p. 535] ; and contrast Zygonectes [1, p. 548], 

 Chologaster [1, p. 549], Siphonops [6, p. 102], Protens [6, 

 p. 72], Typhlops [6, p. 116], and Typhlotriton [3, p. 34], 

 Scalops [8, p. 335], and Talpa [6-, p. 13], in which latter 

 three it can be found by the eye cleft). Of those forms in 

 which the deeply-seated position of the eye is comparable to 

 tliat of Notoryctes, may be mentioned Myxine, Amblyopsis, 

 Rhineura, and especially Troglichthys, in which, as here, its 

 wall is iu contact with the skull. 



There are, however, to be found in Notoryctes in the head 

 region, in common with the region of the modified " ischio- 

 tergal " patch, curious organs formed as modifications of the 

 epidermis. These are presumably tactile in function^ and will 

 be described in detail in Part IV of these Contributions. 



The eye, which is not much more than a hollow ball of pig- 

 ment, lies within the anterior wider end of a fibrous cone- 

 shaped capsule (fig. l,/.c.), 5*25 mm. to 5*7 mm. long, 1*14 

 mm. to 1*75 mm. in vertical diameter, and "7 mm. to '87 ram. 

 in transverse horizontal diameter. This capsule is attached 

 by its small posterior end to the bony Avail of the skull, and 

 passes forwards close against the periosteum of the lachrymal 

 bone, being only partially open in front. This is not to be 

 confused with the fibrous capsule mentioned by Dr. Stirling 

 [11, p. 180], as will be seen later. Structures comparable to 

 this conical capsule are found only in Chologaster papil- 

 liferus [1, p. 550] and Amblyopsis spelfeus [1, p. 560], 

 in each of which cases orbital fat is found inside with the 

 eye and eye muscles ; in Notoryctes, fat has only been seen 

 in one single eye, and that in small quantities. In Siphonops 

 [6, Taf. vii, figs. QQ and 67] a somewhat similar fibrous cone 



VOL. 50, PART 4. NEW SERIES. 40 



