537 
Dutt. — Pityostrobus macrocepkalus , L. and H. 
this figure. Some of the bundles have been cut obliquely longitudinally, 
and such sections show the tracheides of the xylem with uniseriate bordered 
pits on the walls appearing as oval black ‘ discs ’. Protoxylem elements 
with spiral thickenings may be found at the edge farthest from the phloem. 
The bundles in the middle region of the scale are often inclined to one 
another at various angles, and in some cases are so grouped as to suggest 
the incipient formation of a second series : this is particularly the case in 
Mr. Edgell’s specimen of P, macrocepkalus. Dr. Stopes (13) records 
a similar condition in the case of Pinostrobus sussexiensis , Mantell., from 
the Lower Greensand, but in this cone the irregular orientation is more 
marked and a second series of bundles is definitely present. 
4 . The Ovules , 
These form one of the chief features of interest. In a number of cases 
the contents of the ovules are comparatively well preserved and the relation- 
ships of the different structures can be made out with great clearness. The 
integument is thick and tapers at the apex to form a long blunt-ended 
micropylar tube, usually nearly or quite closed, and which is strikingly 
similar in appearance to that of certain Cycadean types. A transverse 
section in this region shows that it is composed almost entirely of heavily 
lignified tissue and has a narrow slit-like micropylar opening (see Fig. 4 , 
PI. XV). This, of course, is common in recent Gymnosperm ovules. Some 
of the ovules are flattened in the plane of the scale on which they lie, and in 
some seeds of P. ovatus the lateral edges are so distinctly ridged as to give 
a marked impression of bilateral symmetry. It is probable that the ridges are 
partly caused by the pincerdike extensions of the wings along the edges of 
the seeds from the base upwards. In the large transverse section of an 
ovule at the left of Fig. 4 , PI. XV, a crack appears to penetrate each of the 
lateral ridges, but, as a matter of fact, the opening is closed to the exterior. 
In the large ovule on the right-hand side of the same photograph the passage 
seen is actually complete, although the section seems to be quite transverse 
and much below the micropylar opening. The effect is probably due to 
external pressure. The base of the ovule frequently exhibits an extensive 
wing tissue at its point of attachment (see W., Fig. 3 , PL XV). Comparison 
may be made with Tubeuf's (15) figure of a longitudinal section of an ovule 
of Pinus excelsa which shows the large parenchyma developed by the wing 
in the same region. There seems no ground for Mr. Gardner’s (5) statement 
that in P. macrocepkalus the seeds are possibly wingless. 
(i) The Integument. 
The thick wall of the integument shows a differentiation into at least 
three layers. The structure, which can be studied to the best advantage in 
the well-preserved ovules of the Sedgwick Museum cone, is identical in all 
