513 
PALAEONTOLOGY OF NEW-YORK. 
there is likewise a small process which may be the radicle, as shown in the ac¬ 
companying fig. 5, of a small specimen preserving the usual form of this species : 
this figure is of the natural size. 
The accompanying fig. 6, of a very beautiful specimen of the G. gracilis , is from 
the same locality as all the others known to me, but shows a greater development 
of the branches and a more distinct serration than any others in the collection*. 
Fig. 6. 
Graptolithus gracilis. 
This one and the preceding species are remarkably slender, and, although serrated 
on one side only, present some marked peculiarities when compared with the singly 
serrated forms with central discs and a bilateral arrangement of the branches, as 
in G. logani , G.Jlexilis and G. multifasciatus. 
The specimens of this species, which have thus far come under observation, have 
still some points relative to the mode of growth undecided. It may have grown, in 
the young state, as shown in figures 1, 2, 3. If, however, the little transverse bar at 
the base indicates the original existence of two similar stipes or main branches in 
addition to those already known, the mode of growth may still have been similar, 
but having four instead of two main branches or stipes. If spread out, as the speci¬ 
mens usually are npon the surface, it may assume the form of the accompanying 
diagram fig. 7. 
* Although the main stipe was represented as continuous, it is nevertheless partially covered in the centre, 
or at the radicle-point by the overlapping of one of the bent branches and a little adhering stone. 
