aOS PALAEONTOLOGY Or NEW- YORK. 



Fig. 4 a, i. A gem or young graptolito, showing the rootlets below and a short axial fibre 

 extending above. This is a broad form, apparently of the doubly serrated kind, 

 or diplograpsus, and appears to bo developed to the first serratures. The figures 

 are respectively of the natural size and enlarged. 

 Fig. 5. A minute specimen of a less symmetrical and apparently less fully developed form. 

 Fig. 6. Another individual which is farther developed than either of the preceding : the line 

 marks the natural size. 



There are several other varieties of form, which, inferring from the central 

 midrib, are of those serrated on the two sides of the stipe, as are all those yet 

 discovered with the vesicles attached. 

 Fig. 7 IB apparently the young of one of the singly serrated forms, from the radical fibre 

 extending along one side and beyond the body, while minute fibres (or rootlets?) 

 extend downwards. 



All these young forms preserve the axial fibre extended beyond the substance 



of the stipe, and there are usually two or three slender fibres exteniied below in 



the direction of the radix. 



The condition of these bodies, and their association with those bearing the sacs, 



are so constant, that I have inferred their connection, and that these are in fact 



the embryonic sacs. 



The collection of specimens is quite numerous; but I am still making additions, 

 with the hope that, at no distant period, we may know something satisfactory rela- 

 tive to this newly observed and peculiar development. 



The following new species of Graptolites appear to be worthy of notice 

 in this place. 



Oraptolitlius niultifasciatus. 



Body consisting of numerous bifurcating branches, which are arranged 

 bilaterally on either side of a short strong central bar. The branches 

 bifurcate irregularly, and the subdivisions on one side amount to 

 twenty-one, and on the other to twenty-two, while ths specimen is far 



