MUSEUM OF COMPARATIVE ZOOLOGY. 5D 
Rhamnee. 
99. Paliurus Zizyphoides, Lx. 2 specimens. 
100. Paliurus tenuifolius, Heer. Leaf small, membranous, ovate, acute, 
entire to near the apex, where it is marked with a few acute small teeth ; lat- 
eral nerves parallel to the borders up to near the apex, where they join the 
secondaries by anastomosing branches ; secondaries opposite, at a great dis- 
tance from the primaries. 
The leaf has the characters of the species as described and figured by Heer, 
Fl. Tert. Helv., III., Plate CXXII. fig. 31, and by Saporta, Ett., I. p. 122, 
Plate XII. fig. 5. Heer, however, says of the leaves that they are very en- 
tire ; but the upper part of the leaf figured by him, Joe. cit., is destroyed, while 
Saporta describes the leaves as subundulate-denticulate. The one which I 
refer to this species, considering it a mere variety, is preserved nearly entire. 
1 specimen. 
101. Paliurus Coloradensis, sp. nov. Leaf small, obovate, obtuse, denticu- 
late above, triple nerved from above the base, with a single pair of opposite 
secondary veins above the middle of the leaf, parallel to the basilar ones, 
acrodrome and branching outside. : 
The top of the leaf is somewhat obliterated ; its nervation is much like that 
of P. ovoideus, Heer, Fl. Tert. Helv., Plate CX XI. figs. 58, 59, Plate CX XII. 
fig. 3. Its size is intermediate between that of figs. 58 and 59. But it greatly 
differs by its obovate form and the position of the intermediate pair of sec- 
ondary nerves, as thick as the primaries and parallel to them. 1 specimen. 
102. Zizyphus fibrillosus, Lx., U. S. Geol. Surv. of the Terr., VII. p. 276, 
Plate LII. figs. 1-6. The specimens of this species are fine, and the petiole 
of one of the leaves is preserved 2 cm. long. The base of the leaves is either 
round, subtruncate, or subcordiform. The largest leaf is nearly 10 cm. long, 
and 7 cm. broad in the middle. 7 specimens. 
103. Zizyphus hyperboreus, Heer. The leaf is like that described in U. 8S. 
Geol. Surv. of the Terr., VIL. p. 276, Plate LI. fig. 15, doubtfully referred to 
Heer’s species described from Greenland specimens. The texture of the leaf 
is coarse, the nerves very prominent ; the nervilles uniting the lateral nerves 
to the borders are at right angles, thick, and the medial nerve has two pairs 
of branches in the upper part. 3 specimens. 
104. Zizyphus, sp. undeterminable. 1 specimen. 
105. Rhamnus Goldianus, Lx. 13 specimens. 
.106. Rhamnus Cleburni, Lx. 7 specimens. 
107. Rhamnus crenatus, sp. nov. Leaf large, ovate-lanceolate, acuminate, 
rounded or subcordate at the base (broken), minutely crenate ; lower lateral 
nerves more open, the upper gradually more oblique, all much curved in pass- 
ing toward the borders, and inclining to the midrib ; the two highest pairs 
acrodrome ; nervilles numerous, close, parallel. 
This fine leaf is 12 cm. long (base and apex broken), 6 cm. broad a little 
above the base. It has the same form, size and nervation as R. grosse-serratus, 
