2 
Oliver and Salisbury . — On the Structure and 
I. Introduction. 
HE object of the following paper is a twofold one. In the first place, 
A to present a detailed account of a small and homogeneous group of 
palaeozoic seeds, the hitherto practically unknown Conostoma group ; in 
the second place, closely to compare these newly-described seeds with 
forms already familiar, viz. with the Pteridospermic seeds, Lagenostoma 
and Pkysostoma, and with Gnetopsis. Thanks to the kindness of Professor 
C. E. Bertrand and the extreme courtesy of Professor H. Lecomte of the 
Musee d’Histoire Naturelle at Paris, we have had at our disposal for com- 
parison the superb and unique series of type specimens of Gnetopsis elliptica 
from the Renault collection. We are thus in a position to state our con- 
clusions after consulting at first hand the whole of the preparations which 
bear on the subject. 
The little-known genus Conostoma was founded by Williamson in 1 877 1 
for the reception of three of the smaller palaeozoic seeds, viz. C. oblongum , 
from the Gannister beds of the Lancashire coalfields, and C. ovale and 
intermedium from the Calciferous Sandstone Series of Burntisland. With 
the Burntisland seeds we have no concern here, as they are under reinves- 
tigation at the hands of Miss Benson. We understand, however, that the 
two species are not really distinct and are being reduced to one, for the 
reception of which, in view of its structural peculiarities, Miss Benson is 
founding a new genus to be named Sphaerostoma. 
Conostoma oblongum is one of the very rarest of Coal Measure seeds, 
and apart from a passing notice by one of us, 2 has not, so far as we know, 
found mention in the literature of Palaeobotany since the publication of 
Williamson’s brief description in 1877. At intervals during the last nine 
years, however, specimens from Mr. James Lomax have been added to the 
University College Collection ; these, together with one from Mr. W. 
Hemingway and two kindly lent us for description by Mr. D. M. S. Watson, 
form the whole of the new material at our disposal. One of Williamson’s 
two type specimens is available for reference in the Williamson Collection ; 3 
his other type, the more valuable of the two, we have been unable to con- 
sult. It is probably in the Butterworth Collection, but we have not been 
successful in tracing the section. 
During the course of our reinvestigation of Conostoma oblongum occa- 
sional sections of what appears to be a closely allied but undescribed species 
came into our hands. The first sections (received in 3904) were from Shore 
and Dulesgate; more recently a series of four transverse sections of a single 
1 W. C. Williamson : On the Organization, &c., pt. viii, Ferns, Gymnospermous stems and seeds. 
Phil. Trans., 1877, P* 243. 
2 F. W. Oliver : On Pkysostoma elegans. Ann. of Bot., vol. xxiii, pp. 99, 105, and no. 
3 Nos. 1443 and 1444. 
