47 
Trigonocarpus Shorensis , sp. nov. 
At the base this decreased to under 3 mm., but the almost sudden concavity 
of the sclerotesta at the micropyle gives the sarcotesta in that region 
a maximum thickness of nearly 6 mm. Although our highest sections 
pass not far below the apex no flattening is exhibited, but the sarcotesta 
curves inwards equally on all sides. This is in conformity with the 
impressions of seeds attached to Neuropteris heterophylla and Neuropteris 
obliqua described by Kidston 1 and Kidston and Jongmans. 2 
The junction of the sclerotesta with the sarcotesta, composed as the 
latter was of thin- walled cells, appears superficially as a sudden change, 
but the innermost cells of the sarcotesta can be recognized as direct con- 
tinuations of the rows of sclerized elements. It is only in tangential or 
longitudinal sections that this transition can be properly seen, since the 
innermost sarcotestal cells, which are elongated and tubular (0-15 mm.- 
0-35 mm. xo '033-0-049 mm.), are directed obliquely outwards and upwards 
(PI. IV, Fig. 5). Owing to this the transition, which was of equal 
gradation throughout, appears much more sudden in transverse sections 
through the middle region than in those through the base or apex, where 
the surface is cut obliquely. This may perhaps be true also of the similar 
observations of Scott and Maslen 3 for T. Parkinsoni. 
Very frequently cells comprising the innermost layer of the sarcotesta 
are seen cut longitudinally, also in tangential sections (PL IV, Fig. 5, st. c.) 
these cells alter their direction in a similar sinuous manner to those of the 
outer sclerotesta. Here and there slight thickening of the walls can be 
detected, and the intercellular spaces are either very minute or completely 
absent. It is clear, then, that the structure of the cells and architecture of 
the innermost tissue of the sarcotesta were essentially the same as in the 
outer layers of the sclerotesta — a continuity of structure which can only be 
reconciled with a homogeneity of origin. As we pass further outwards 
the intercellular spaces become more and more pronounced, and the con- 
stituent cells, at first tubular, very quickly become more rounded, and pari 
passu , as we pass to the exterior, develop irregularities in the form of pro- 
jections which connect on to those of adjacent cells and give an almost 
stellate structure to the tissue (Text-fig. 6). 
Owing to the rounded character of the middle sarcotestal cells, the 
intercellular spaces between them were of more or less equal dimensions in 
every direction. At a very little distance out, however, the cells were 
slightly flattened, and tend, especially at the periphery, to form short 
vertical series separated from one another by elongated lacunae. Sections 
in this plane also show that the arms or projections of successive cells were 
often superposed, so that each large lacuna is frequently without trabeculae, 
1 On the Fructification of Al. heterophylla. Proc. Roy. Soc. London, vol. cxcvii, 1904, p. 1. 
2 Archives neerlandaises d. sci. exactes et naturelles, s£r. iii, B, tome i, 1911, p. 25. 
3 Ann. Bot., vol. xxi, No. lxxxi, 1907. 
