120 



MEDULLOSEAE 



[CH. 



an inner flesh. Transverse sections show that the sclerotesta 

 has three sharp longitudinal keels with corresponding furrows 

 on the inner face, and between each pair of main ribs are 2 3 

 less prominent ridges, usually 12 in all (fig. 426). The sarcotesta 

 consists of thin- walled parenchyma passing externally into a 



c - 



FIG. 424. 



Trigonocarpus. 1. Section of imperfect seed showing a micropyle; 

 b, sclerotesta; c, cast of seed-cavity; 2, 3, apical and basal view 

 of seed-cast. (Approximately nat. size.) M. S. 



FIG. 425. 



B 



Trigonocarpus Parkinsoni. 



A. Impression showing the nucule and sarcotesta. (= Carpolithes 



alata Lind. and Hutt.) 

 Specimen with long micropyle. (A, nat. size; from the Lower 



Coal Measures of Kilmarnock; B, nat. size; Middle C. M. of 



Yorkshire. Kidston Coll., 1579 and 1062.) 



B. 



