62 Excerpta Botanica. 
XII.—Excerpta Botanica, or abridged Extracts translated 
Srom the Foreign Journals, illustrative of, or connected with, 
the Botany of Great Britain. By W. A. Leicuron, Esq., 
B.A., F.B.S.E., &c. 
No. 2. On the mode of Growth of the Ophioglossee. By 
ALEX. Braun. (Ann. des Sc. Nat. n. 8. xiii. p. 63.) 
Tue cellular body from which, in the genus Ophioglossum, 
the leaves arise, is not a sheathing leaf, nor of the nature of a 
stipule or a ligule ; but is, in reality, a cellular body envelop- 
ing the centre of development, on the exterior of which centre 
the leaves are arranged in a regular spiral order, and in which 
situation they continue until their expansion, which, in Ophio- 
glossum vulgatum, takes place in the fourth year. In this 
body each leaf occupies its own particular cellule, which, en- 
larging with the growth of the leaf, is in succession elevated 
into a conical form and becomes finally ruptured like a sheath. 
The spike in Ophioglossum is axillary, and is the solitary leaf 
of a bud developed in the axil of the sterile leaf, to the stalk 
of which that of the spike is agglutinated. In the genus 
Botrychium, at least in the advanced state in which alone it 
has been hitherto examined, this enveloping cellular body 
does not exist, but the leaves ensheath each other. M. Braun 
considers the cellular body in Ophioglossum as a thalloid for- 
mation remaining during the entire life of the plant, and cor- 
respondent to the cellular organ through which the primary 
leaves of germinating ferns penetrate, and to which the name 
of proembryo has been given. As in the Phanerogame the 
first commencement of a plant gives birth to a leaf developing 
itself in the interior of a cellular organ (the sac embryonaire), 
so it would appear that throughout the whole vegetable king- 
dom the formation of a thallus precedes the formation of 
leaves. 
PROCEEDINGS. OF LEARNED SOCIETIES. 
GEOLOGICAL SOCIETY. 
December 4, 1839.—A paper was first read, entitled ‘‘A Descrip- 
tion of the Soft Parts and of the shape of the Hind Fin of the Ichthyo- 
saurus, as when recent,”’ by Richard Owen, Esq., F.R.S., F.G.S. 
The osseous frame-work of the fin of the Ichthyosaurus, Mr. Owen 
observes, having alone been the subject of direct examination, the 
exact shape and the nature of the soft parts had been matters of 
conjecture. A very striking deviation from the reptilian and mam- 
malian types had, indeed, been recognised, and resemblance also to 
