THE PINEAL BODY 143 



many reduplications in its walls. It is rich in blood vessels 

 and has a small cell content. Over it lies the chorioid plexus. 



2. Eutaenia sirtalis. Sorensen ('94). 363 The epiphysis in this 

 species is globular in form and glandular in structure. It is 

 embedded in connective tissue. Herrick ('91) l76 agrees in these 

 observations. 



3. Tropidonotus natrix. Studnicka ('93) ; 384 Leydig ('97). 24 

 In this form there is a paraphysis and epiphysis in older embryos 

 and in the adult. The epiphysis is definitely glandular in char- 

 acter. There is a thin stalk, the latter probably secondary 

 and not analogous to the stalk in lower forms. Ssobolew 364 in 

 1907, working on embryos of Tropidonotus natrix and Vipera 

 berus, found that the epiphysis develops earlier than the para- 

 physis. The parietal eye does not appear in either of the forms 

 studied, nor is there a parietal foramen. The cells of the epi- 

 physis are arranged in colonies as in the glands of internal secre- 

 tion. The organ seems to have nothing to do with light per- 

 ception and the same applies to heat perception. There is no 

 parietal nerve and the primitive canal in the organ is lost (fig. 69). 



4. Tropidonolus rhombifer. Sorensen ('94) , 363 The epi- 

 physis is glandular in character. 



5. Bascanium constrictor. Sorensen ('94). 363 In the embryo 

 of this species the epiphysis has a glandular form and is con- 

 nected with a stalk to the roof of the interbrain (fig. 70). 



6. Coluber aesculapii. Studnicka ('93). 384 In this species 

 the epiphysis is globular in form and covered with connective 

 tissue. It contains a dark pigment and lies close to the brain. 



7. Coronella austriaca. Leydig ('97). 24 There is no parietal 

 organ in this species in relation with the skull. In the embryo 

 the epiphysis is well developed. 



8. Pelias berus. Hanitsch ('88); 169A Studnicka ('93). 384 In 

 this species Hanitsch believed that he discerned a parietal organ 

 with much pigment and a lens. Studnicka disagrees with this 

 and describes the epiphysis as a typically glandular structure. 



9. Vipera ursinii. Leydig ('97). 24 In this species the struc- 

 ture is definitely glandular. 



CHELONIA. 1. Chelone mydas. Rabl-Ruckhard ('86) , 322 In 

 this species the epiphysis is a massive, bilobed structure. 



