1 
Desor on the Embryology of maires, &c. 17 
structure of the yolk granules and the oil drop (4) inside, ing isolated by 
Yn 9- 12. The oil-drop isolated in various shapes, showing its 
elasticity. 
Fic. 13. A flask on the third day, showing the beginning of the divi- 
e the oil-drop being still undivided. 
. 14. A flask 5 days old. The division is more advanced. When 
a yolk breaks (5), each division is an independent sphere, having a eem 
spot inside. 
` Fre. 15. A flask 7 days old. The division is still more advanced ; is 
yolks are flattened at their points of contact. In one of them the primitive 
oil drop is preserved (2). 
Fie. 16. A flask 9 days old. The yolks are so divided as to assume the 
mulberry form. One of them (a) is retarded in its development, show- 
ing merely the beginning of the division with the entire oil drop (a). 
Fic. 17. A flask 12 days old. The embryos are surrounded with little 
cilia, by means of which they revolve. 
Fic. 18. A flask 15 days old. The embryos have inside a clear cres- 
centic spot, the first indication of the intestinal tube 
Fic. 19. One of the embryos compressed, showing that it is composed 
of two zones. : 
Fic. 20. A flask 18 days old. The difference of tissue is obvious in 
all the embryos. 
Fic, 21. A single embryo from another flask of the same age, com- 
pressed, showing three distinet zones 
Puate II. Fic. 22. A flask 24 days old. The external envelop has 
fallen off in one of the embryos, allowing it to move freely in the flask. 
Fic. 23. An embryo, after having escaped from the flask, in an expanded 
state, showing the crescentic spot (c) in an elongated form 
c. 94. The same embryo contracted. 
Fic. 25. An embryo inside of its envelop, the cilia being distinctly vis- 
ible inside. 
Fic. 96. An embryo whose envelop is falling off. 
Fic. 27, An embryo at the moment when it escapes from its envelop. 
(80 diam.) 
Fic. 28. The same dragging its envelop after him. (80 diam.) 
Fic. 29.. An embryo 30 days old; showing the intestinal tube running 
along the body. (80 diam.) 
Fic. 30. An embryo 34 days old. "The intestinal tube is bent inside of 
the yolk residue, which becomes more and more transparent. (80 diam.) 
Fic. 31. Section across the embryo of fig. 29, in order to show the 
structure of the different zones, (400 times magnified) ; m, external envelop ; 
JOURNAL B. S. N 3 
