GRAPTOLITES OF NEW YORK, PART 2 2/5 



In the Monograph oj British Graptolites the family Leptograptidae, 

 based mainly on the morphology ol the thecae, is given the compass it had 

 when proposed by Lapworth in 1879. ^ there comprises both the pauci- 

 ramous and multiramous forms, among the latter also Nemagraptus. While 

 the family thus conceived contains a large variety of types of arrangement 

 of branches, it is well defined by the form of the thecae and slender char- 

 acter of the branches, and clearly in equipoise with the other families, as 

 e. g. the Dichograptidae. 



With our present knowledge of the phylogeny of these forms it may 

 not yet seem practicable to subdivide these large families. Nevertheless, 

 we do not doubt that eventually the peculiar group of forms represented by 

 Sigmagraptus and Nemagraptus will demand recognition as a subdivision 

 of the family. In recognition of both, the general affinity of the Lepto- 

 graptidae and the closer one of the group of genera here mentioned, we 

 have united the latter in a subfamily of the Leptograptidae. Since the 

 term Coenograptus has lost its validity to Nemagraptus we have termed 

 this subfamily the Nemagraptidae. 1 Fuller details of the apparent phylo- 

 genetic relations of the genera of the Leptograptidae have already been 

 given in the introductory chapter on phylogeny. 



The genus here under discussion is currently known as Coenograptus 

 Hall. Its genotype is G rap toli thus gracilis, described by Hall in 

 volume 1 of the Palaeontology of New York [1847]. It is set forth in the 

 Monograph of British Graptolites that Emmons in 1855 described quite 

 obviously the same form as Nemagraptus elegans, thus creating a 

 synonym of Hall's species, but at the same time proposing a new generic 

 name. The generic terms Stephanograptus and Helicograptus were then 

 proposed for the same form about a decade later by Geinitz and Nicholson 

 respectively. None of these names found recognition and Hall [N. Y. 

 State Cab. 20 An. Rep't, 1868, p. 21 7] proposed the generic term Coeno- 

 graptus at about the same time, ignoring Emmons's and the others' earlier 



1 The term Nemagraptidae was originally applied to the Leptograptidae and being 

 replaced by the latter term has become available for this subdivision. 



