2iS Jeffrey. — On the S true hire of the Leaf in Cretaceous Pines. 
Prepinus , shows no tendency whatever towards the Araucarian type of 
bordered pits. 
In this enumeration no account is taken of anything but sporophytic 
features. The gametophytes can more conveniently be considered at 
a later stage, when certain investigations have been completed. 
Before summing up the results of the present research, it is necessary to 
say something in regard to the interpretation of transfusion tissue originally 
put forward by Worsdell and more recently elaborated by Bernard. In his 
article on ‘Transfusion Tissue’ (Trans. Linnean Society, London, vol. v, 
Part 8, Second Series), Mr. Worsdell makes the following statement : 
‘ Transfusion tissue, which occurs almost universally in the leaves of 
Gymnospermous plants as an auxiliary conducting-system, has phylo- 
genetically been derived from the centripetally-formed xylem of the vascular 
bundle, and is thus, morphologically, an integral part of the bundle itself.’ 
The present research strongly supports the general accuracy of Mr. Wors- 
dell’s conclusions. It is, however, rendered doubtful if the elongated pitted 
elements found by this author on the ventral side of the protoxylem of the 
leaf-bundle in many Conifers can in reality be regarded as vestigial centri- 
petal tracheids. It seems much more highly probable, from the conditions 
observed in Prepinus and in species of Cretaceous Pinus , that such elongated 
elements with bordered pits are in reality vestiges of the ancestral inner 
transfusional sheath, the real centripetal xylem having disappeared at 
too early a stage to be represented even vestigially in living Conifers. 
In any case it will not do to characterize, without qualification, the trans- 
fusion tissue which occurs ventrally to the protoxylem in many Coniferous 
leaves as centripetal xylem, as has been the tendency on the part of recent 
authors. 
Summary. 
i. A primitive Abietineous type, closely related to Pinus and strongly 
resembling superficially the Leptostrobus of Fontaine and the Pinites Solmsi 
of Seward, has been found in the Middle Cretaceous (Raritan or Upper 
Potomac) of Kreischerville, Staten Island, N.Y. 
3. It is characterized by the possession of short-shoots or brachyblasts 
of a generalized type, which were deciduous ; but bore numerous spirally 
arranged instead of few verticillate fascicular leaves. The sheath of these 
short-shoots more nearly resembled that found in the section Strobus and 
allied sections of Pinus , but the component scales were not deciduous as 
in the Soft Pines. 
3. The leaves attached to the brachyblasts differed from the fascicular 
leaves of Pines in having their paired resin-canals continuous to the very 
base. The leaves further possessed well-marked centripetal xylem. About 
the foliar bundles was present a complicated double sheath of transfusion 
