Palaeontologie. 
85 
Jeffrey, E. C., On the structure of the Leaf in Cretaceous 
Pines. (Ann. of Bot. Vol. XXII, p. 207—220 with 2 plates, 1908.) 
The leaves described and figured in this paper belong to a 
primitive Abietineous type, closely related to Pinus, and strongly 
resembling superficially the Leptostrobus of Fontaine, and the 
Pinites Solmsii of Seward. They were found in the Middle Creta¬ 
ceous (Raritan or Upper Potomac) of Kreischerville, Staten 
Island, N. Y. 
A new genus Prepinus is proposed for these specimens, in the 
belief that this fossil is the direct ancestor of Pinus. A new species, 
Prepinus statenensis is instituted. It is characterised by the posses- 
sion of short shoots or brachyblasts of a generalised type, which 
were deciduous; but bore numerous, spirally arranged, instead of a 
few, verticillate, fascicular leaves. The sheath of these short shoots 
more nearly resembled that found in the section Strohns and allied 
sections of Pinus, but the component scales were not deciduous as 
in the soft Pines. 
The leaves attached to the brachyblasts differed from the fasci¬ 
cular leaves of Pinus in having their paired resin-canals continuous 
to the ver 3 T base. The leaves further possessed a well-marked, cen- 
tripetal xylem. A complicated double sheath of transfusion tissue 
was present, closely related to the centripetal wood, and resembling 
that found in some Cordaites. Many of the Middle Cretaceous pos¬ 
sessed this sheath, but entirely lacked the centripetal wood. The 
elongated pitted elements on the ventral side of the protoxylem in 
existing Coniferous leaves appear to be relics of the inner trans¬ 
fusion sheath, and not of true centripetal x}dem. 
The author regards the Abietineae as the oldest living famil}^ of 
the Coniferales, and Pinus as the oldest living representative of the 
famity, in all probabilitv derived from Prepinus. The arguments for 
this view are as follows. The Abietineae possess marked vestiges of 
a double leaf-trace, and, in Prepinus, true centripetal wood, and a 
complex double sheath of transfusion tissue occurs, the latter being 
absent in the Middle Cretaceous Araucarineae. There is also evidence 
that the ancestral Araucarians were derived from an Abietineous 
stock. Arber (Cambridge). 
Kidston, R., On a new species of Dineuron and of Botryo- 
pteris from Pettycur, Fife (Trans. R. Soc. Edinburgh, Vol. 
XLVI, Part II, No. 16, p. 362—364 with a plate, 1908.) 
These two new species are derived from the Calciferous Sand¬ 
stone (Culm) of Scotland. Dineuron ellipticum n. sp. is the first 
example of the genus recorded from Britain. It is an almost cir¬ 
cular petiole with a maximum diameter of about 2.25 mm. The outer 
cortex is stout, and consists of thick-walled prosenchyma, and the 
inner, of a narrow band of delicate cells. An endodermis is present, 
but the thin-walled elements of the Stele have mostly disappeared. 
The elliptical xylem mass is composed of large tracheae without any 
admixture of parenchyma. Towards its two extremities the tracheae 
suddenly become smaller where the} T meet the protoxylem elements. 
At one side of the xylem mass, a circular opening occurs, surroun- 
ded by protoxylem elements. On the other side a semicircular sinus 
is observed, which results from the Separation of a portion of the 
xylem to form the outgoing pinna trace. The mode of departure of 
