STUDY OF THE GRAPT0LITE8. 



215 



Fig. 2S. 



while the slender alternating pinnulo3 are flat and simple, as they have 

 been observed in numerous individuals. The specimen represented is 

 even less curved than the usual con- 

 dition of this species in the slaty 

 Trenton limestone of Wisconsin. 



Still more obscure, and perhaps 

 remote in its analogies with Grap- 

 tolites, is the Genus Inocaulis, 

 consisting of flattened scabrous 

 stems, associated with Dictyone- 

 MA in the shale of the Niagara 

 formation, which, from their car- 

 bonaceous substance and apparent 

 graptolite texture, I have referred 

 to the Graptolitidce (fig. 28, Ino- 

 caulis jjlumidosa*). 



II. Structure of the Ch^axitolite. 



In the study of the Hydrozoa, some terms have been applied to these 

 bodies and their several parts which are equally applicable to the Grap- 

 tolite family, as one of the same order of animal structures. The word 

 " polypary," a term long in use among the Zoophytes, emln'aces the 

 entire animal body whether simple or compound, and is perhaps prefer- 

 able to the simple '■'■ froncV or " stipe,''' which are properly botanical terms. 

 In the nomenclature adopted for the Hydrozoa, the parts developed by the 

 nutrient and generative functions have given origin to the term ^Hropho- 

 some" for the one and "gonosome'''' for the other ; and the term "coenosmr'' 

 not only applies to the common body or common fleshy basis of the 

 colony, but to the individual polypites occupying the cells or "hi/drotheca." 

 The initial point or radicle is termed the "h//drorhi.m;" the non-cellulife- 

 rous portions, or the part intervening between the initial point and the 

 commencement of the cellules, is termed the "hydrocaulus;''^ and the repro- 

 ductive or generative buds are termed '■^gonophores.'" 



There may be many advantages in the use of these terms, though 

 they do not cover all the ground required by the Graptolites, which pre- 



* The specimens of this fossil are extremely obscure, and the figure does not properly represent 

 its characters. It is not however, a solid stem; and though, as has been asserted, it may not 

 belong to the Graptolitidas, no other relation has yet been proved. 



