part 2] GEOLOGICAL HISTORY OF THE GENUS STBATIOTES. 119 



fossilization, but traces of it may frequently be seen clinging to 

 the surface of the fossils. (ii) A thin woody layer ornamented 

 ■externally by a series of pits arranged more or less regularly in 

 longitudinal rows. (iii) A thin, closely adherent skin lining the 

 seed-cavity, which consists of elongate spirally- thickened cells with 

 double walls crossed by fine canals (see PI. VI, fig. 22). The 

 woody layer (i), as a rule, forms the surface in the fossils ; the thin 

 inner skin (iii) is frequently well-preserved, and in all species it 

 shows the same microscopic features. 



Ventral 

 Side 



Fig. 2. 

 Apex 



neck-. 



collar 



micropyle ' 



..--..ki 



testa 

 tegmen. 



micropyle — ' 



'-chalaza 



■ — raphe 



Dorsal 

 Side 



The proximal end of the seed with its collar is defined as the 

 base, and the opposite end as the apex; the keeled edge is the 

 dorsal, and the opposite edge the ventral side. 



In germination the testa splits into symmetrical halves from the 

 base along the keel to the apex, and, although these halves may 

 remain joined for a time, they eventually fall apart. 



The interior of the seed shows the basiventral micropyle, passing 

 through the wall either very obliquely, horizontally, or in a reflexed 

 manner, and narrowing markedly towards the exterior ; it also 

 shows the raphe traversing the length of the keeled dorsal margin 

 diagonally, and entering the cavity at the apical chalaza (see text- 

 figure 2, above, and PL VI, fig. 20). 



k2 



