ON THE STRUCTURE OF LAGENOSTOMA OVOIDES, 461 
On the Structure of the Paleozoic Seed Lagenostoma ovoides, Will. Ву 
THEoporA L. РкАхКЁвр, B.Sc., University College, London. (Com- 
municated by Prof. Е. W. Омукв, F.R.S., F.L.8.) 
(PLATES 22-24 and 3 Text-figures.) 
( Read 2nd May, 1912.] 
CONTENTS, 
Page 
I. Introduction 2.0.2... eee 461 
П. General Description. 
A. External еее eee 462 
B. Internal ................................ 463 
C. Terminology .............................. 465 
III. Detailed Structure. 
A. Integument .............................. 466 
B. The Vascular System ...................... 472 
C. The Nucellus ............................ 475 
D. The Pollen .............................. 477 
Е. The РгоШайц#............................ 478 
Е. Fungus еее зан 479 
IV. The Nield Specimen .............................. 480 
V. Theoretical Suggestions .......................... 481 
VI. Literature cited .................................. 487 
I. INTRODUCTION. 
THE form-genus Layenostoma was established by Williamson (20) for the 
reception of those seeds which were characterized, among other peculiarities, 
by the modification of the писеПаг apex into a flask-shaped organ for the 
reception of pollen, which he termed the lagenostome. 
Three species of his genus were distinguished by Williamson :— 
(i) L. Готахи, some sections of which he partly described in his MS. 
catalogue (now in the British Museum, 8. Kensington), and which has since 
been fully dealt with by Oliver and Scott (16). 
Gi.) L. physoides, to which he had previously referred as Physostoma, and 
of which a complete account has recently been given by Oliver (14) under 
that name. 
Gii.) L. ovoides, of which, with L. physoides, he gave some description in 
1877, based on preparations made with his own hands from the few 
specimens then available (20). 
Two other species of Lagenostoma have been described (1) from impressions 
LINN. JOURN.—BOTANY, VOL. XL. IK 
