S19 



PALEONTOLOGY 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 siHJcies : 

 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 mc, but shows a greater development 

 of the branches and a more distinct serration than any others in the collection*. 



Fio. 6. 



Graptolithns 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. mulfifasciatus. 



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 jn 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 wa.s represented as continuous, It Is nevertheless partially covered in the centre, 

 or at the radtclc-point by the overlapping of one uf the bvnt branches and a little adhering stone. 



