Of the Thorn-Back's Eggs. 



the Nourifhment of the included 

 Foetus. The whole inclofed Sub- 

 ftance has its Membrana communis like 

 all other Eggs, which lines the whole 

 Cavity of the Shell; the Albumin a 

 alfo, and Vitellus or Yolk, have their 

 feparate Involucra, or Membranes. 

 This Yolk however is not fufpended 

 by its Poles, as that of other Eggs 

 are, the Chalaza? not being neceflary, 

 I fuppofe, in an Egg of this Shape. 

 The Cicatricula alfo is extreamly 

 plain even to the naked Eye, and 

 appears rayed fomething like the 

 tranfverfe Se&ion of a Lemon, which 

 (hews that thefe Eggs are fecundi- 

 fied before Depofition. The De- 

 fcription of them, which I have given 

 here, as well as Delineation, Plate 

 V. Fig. 1 6. were taken from Eggs 

 immediately extracted out of the 

 Ovary, or Uterus of the Female 

 Thorn-Back. 



CHAR 



