CH. Xlll] 



EMBRYOLOGY. 



177 



pastoris) in the manner described in the Practical Work, 

 No. xiii. 



FIG. 82 



A. OPTICAL SECTION THROUGH THE OVULE OF THE SHEPHERD'S 



PURSE (CAPSELLA). 

 F, funicle ; M, micropyle ; E, embryo. 



B. STAGES IN THE DEVELOPMENT OF THE EMBRYO. 



1, suspensor, bearing below the undivided embryo-cell. 



2, embryo (i.e. excluding the stalk or suspensor) consists of eight cells. 



3, the primary epidermis has appeared: h is the hypophysis, i.e. the last 



cell of the suspensor. 



4, the primary vascular cylinder (shaded) has appeared: the hypophysis 



has divided, part goes to make part of the embryo. 



5, 6, older stages : 6, with well-formed cotyledons (C). 



The first stage (which is not shown in fig. 82) is the 

 division of the egg-cell into two parts ; one, which may be 

 called the upper cell, being next to the micropyle end, 

 while the lower cell points to the cavity of the embryo-sac. 

 The latter, which is called the embryo-cell, gives rise by 

 cell-division to nearly the whole of the embryo ; the upper 

 half gives rise to a simple row of cells called the suspensor, 

 because, by it, the main body of the embryo is hung as by 

 a stalk. The minute swollen head at E in fig. 82, A, is the 

 very young embryo and the stalk, by which it hangs from 

 the micropylar end of the embryo-sac, is the suspensor. 

 D. E. B. 12 



