PLATE 73. 
1. 323. 4. Graptolithus mucronatus. (Pag. 268.) 
1 a. Two fragments of this species. 1 b. A portion of one enlarged. 
1 c, d. Fragments of the same species, one of them much contracted, and both preserving extremely mucro- 
nate teeth. 
2. • 324. 5. Graptolithus bicornis. (Pag* 268.) 
2 a. A small specimen of the natural size, showing the bifurcation below. 
2 b. A portion of the same magnified, showing the form of the teeth. 
2 c. A larger specimen having the same character, with a stronger bifurcation, which is thickened at the point 
of separation. 2 d. A portion magnified. 
2 e. A specimen having similar obtuse teeth, with the base removed and the midrib projecting above. 
2 f A fragment of slate, with several specimens preserving the peculiar radical termination; associated with 
G. ramosus. 
2 g, h. Magnified portions of these, showing a dissimilar form in the teeth. 
2 i. A fragment in the slate, preserving its original form in a good degree. 2 k. The same enlarged. 
2 l. A fragment in limestone. 2 V. A more compressed form in the same. 
2 m, m'. Enlarged portions of the same. 
2 m". A magnified view of the edge of a specimen in limestone, showing an appearance analogous to G. sca- 
laris. 2 n. Transverse sections of the same magnified. 
2 o. A slender specimen, with the sides parallel. 
2 p. A similar specimen, preserving the capillary axis beyond the remaining portion of the stipe. 
2 r, s. Magnified portions of these, showing their identity with the preceding. 
3. 325. 6. Graptolithus ramosus. (Pag. 270.) 
3 a, a'. Small specimens near the radical termination, having a simple bifurcation above. 
3 b. A specimen with a more diverging and elongated bifurcation, with a smaller specimen lying obliquely 
across the right ramus. 
3 b' & b". The same species. 3 c, d. Enlarged portions of the two last. 
3 e. A specimen with elongated rami, which are serrated on one side only. Fragments of G, Sagittarius on 
the same specimen. 
3/. A specimen branched below, and bifurcating above. The branches and bifurcate stipe above are serrated 
on one side only; while the stipe below and between the branches and bifurcation is serrated on both 
sides. 
3 g, h. Enlarged portions, showing the character of the teeth at the points of divergence, below and upon the 
branches. 
4. 326. 7. Graptolithus scalaris. (Pag* 271.) 
4 a. A specimen showing the radical termination. 4 b. A portion of the same magnified. 
4 c. A more slender and tapering specimen, with a single range of dissepiments. 4 d. Magnified portion. 
4 e,f. A small fragment, with oblique dissepiments and smooth margin. 
4 g, A specimen with apparently a single range of dissepiments, and a central capillary axis projecting beyond 
the stipe. 
