570 ON THE PLURALITY AND DEVELOPxMKNT 



duction or separation of a distinct body within the nucleus 

 of the ovulum, which, before impregnation, is a sohd 

 uniform substance. 



370] In this stage the upper extremity of the included body, 

 or amnios, is slightly concave, and has a more or less rough 

 or unequal surface ; the inequality being in consequence of 

 the laceration of the cellular tissue, by which it was in its 

 early stage attached to the apex of the original nucleus, or 

 rather to a short cylindrical process arising from it and 

 corresponding in size and form with this concave upper 

 extremity, from whicb it separates when the amnios has 

 attained its full size. 



On this concave upper extremity of the amnios a few 

 minute points of a deeper colour, and disposed in a single 

 circular series, are sometimes observable ; in general, how- 

 ever, they are hardly to be distinguished. 



Below the concave apex the amnios itself is slightly 

 transparent for about one fourth of its length, the remain- 

 ing, portion being entirely opake. 



On dividing the whole longitudinally it is found to con- 

 sist of a pulpy cellular substance, in which no definite cavity 

 is originally observable ; the upper transparent portion is, 

 however, of a looser texture, and on the included embryos 

 becoming manifest, a cavity irregular both in figure and 

 extent is formed in its centre. 



But before the embryos themselves or their funiculi 

 become manifest, the areolae, or portions of the substance 

 destined for their production, are visible. 



These areolae, as 1 observed them in the conniion larch 

 in May, 1827, are from three to five in number, of nearly 

 cylindrical form, arranged in a circular or elliptical series, 

 and are seated near the apex, with which they probably 

 communicate by the similarly arranged points of its surface 

 already noticed. 



In the amnios of Piniis si/lvestrisy as observed in June 

 and July last, the corresponding parts were found con- 

 siderably more advanced. In the specimens then examined, 

 the remains of the embryoniferous areolae, from four to six 

 in number, were still visible, but consisting of conical mem- 



