JNDEX. 



655 



influence of on early development, 

 282, 283 



Yolk-sack, Amphibia, 108, 115, 11G; en- 

 closure of, 101 



Yolk-sack, development of in Rabbit, 188 ; 

 of Mammalia reduced, 188; circulation 

 of in Eabbit, ( 193 ; 'enclosure of in Sauro- 

 psida, 240 



Yolk-sack, enclosure of, Petromyzon, 70 



Yolk-sack, Lepidosteus, 97 



Yolk-sack of Chick, enclosure of, 133 ; 



stalk of, 142; general account of, 161 ; 



circulation of, 162 ; later history of, 164 

 Yolk-sack of Elasmobranchii, enclosure 



of, 51, 236 ; circulation of, 52 

 Yolk-sack of Lacerta, 173; circulation of, 



173 

 Yolk-sack, Teleostei, 61, 65; enclosure of, 



60 ; circulation of, 66 



Zona radiata, villi of, 195 

 Zouula of Zinn, 407 



