74 Oliver.— On Phy so stoma elegans , Williamson , 
name Physostoma elegans l A year or two later, a description of this seed 
was included by Williamson in his eighth Memoir , 2 but, owing to the 
imperfect character of the material at that time available for study, he placed 
it provisionally in his new genus Lagenostoma ) under the name L. physoides— 
the other member being Lagenostoma ovoides. To these he added in his 
manuscript catalogue a third species, Lagenostoma Lomaxii , a seed which 
recent investigation proves to have been borne by Lyginodendron . 3 
In addition to these three species of Lagenostoma — all petrified seeds 
from the Lower Coal-Measures of Lancashire and Yorkshire — additional 
species have been discovered preserved as casts. These include the fully- 
described L. Kidstonii and L . Sinclairii , of Arber , 4 and one or more species 
discovered by Grand’Eury , 5 and referred to Sphenopteris Dubuissonis , and 
other forms. To these casts further reference will be found at p. 113 of 
the present paper. 
With these seeds must be associated one or more of the species of 
Williamson's genus Conostoma , 6 more particularly Conostoma oblongum , one 
of the rarer of our English Coal-Measure seeds. 
The present communication deals with Lagenostoma physoides , the 
further study of which has entirely corroborated Williamson's opinion as to 
its ‘ very distinct 5 character. 
As the material for a detailed description is now adequate and abundant, 
the time has arrived when effect may be given to Williamson’s original 
intention in the matter of nomenclature. In pursuance of this it is proposed 
to revive for this seed the abandoned generic name Physostoma , a course 
which seems free from serious objection. As regards the specific name, 
alternative courses seem open. The name physoides might be retained, or 
Williamson’s original name, Physostoma elegans , which is both euphonious 
and appropriate, might be revived. It is proposed to follow the latter 
course. 
Since the appearance of Williamson’s description in 1877, based on two 
imperfect longitudinal sections of a single specimen, 7 a few additional facts 
regarding the structure of Physostoma have been placed on record. Under 
the name of Sporoearpon ornatum , Williamson described and figured poorly 
preserved transverse sections of Physostoma in his tenth and twelfth 
1 W. C. Williamson, On some ossil seeds from the Lower Carboniferous beds of Lancashire, 
Brit. Ass. Reports (Bristol) 1875, p. 159. 
2 W. C. Williamson, On the Organization, &c., pt. viii, Ferns, Gymnospermous Stems, and 
Seeds. Phil. Trans., 1877, p. 241. 
3 Oliver and Scott, On the structure of the palaeozoic seed Lagenostoma Lomaxii > &c., Phil. 
Trans. B., vol. cxcvii, 1904, p. 193. 
4 E. A. N. Arber, On some species of Lagenostoma , Proc. Roy. Soc. B., vol. lxxvi, 1905. 
5 C. Grand’Eury, Sur les graines de Sphenopteris, etc; Comptes Rendus, t. cxli (1905), p. 812. 
0 Williamson, eighth Memoir, p. 243. 
7 The sections are in the Williamson Collection, now in the Department of Geology, Natural 
History Museum, and correspond to the numbers 1439 and 1440. 
