186 TWENTIETH REPORT ON THE STATE CABINET. 



II. STRUCTURE OF THE GRAPTOLITE. 



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

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

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

 "POLYPARY," a term long in use among the Zoophytes, embraces the 

 entire animal body whether simple or compound, and is perhaps preferable 

 to the simple "■frond'"' 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 " tropho- 

 S07iie " for the one and " gonosome " for the other ; and the term " coenosarc'^ 

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

 but to the individual polypites occupying the cells or ^'- liydrotheca.'" The 

 The initial point or radicle is termed the "■ hydrorhiza ;"*' 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 

 reproductive or generative buds are termed " goiKyphorts."" 



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

 do not cover all the ground required by the graptolites, which present a 

 certain development of form and parts not met with in the ordinary forms 

 of Hydrozoa. The central .disc of the compound forms requires a special 

 designation ; and the little bar or funicle connecting the two halves of the 

 frond or polypary should be distinguished from the barren portions of the 

 stipes or branches which rise from it, and we must still use the distinctive 

 term ' ' solid axis . " 



In the present paper, I shall have 'less hesitation in the use of the 

 simple and more easily understood terms, because the larger proportion of 

 the copies will fall into the hands of those who will more readily compre- 

 hend and apply them. Following the preceding discussion of the general 

 character and forms among the G-raptolitid^, we proceed to consider 

 the different parts, beginning with the initial point. 



III. CENTRAL OR BASAL PORTIONS OF THE GRAPTOLITE. 



1. The radicle or initial point [hydrorhiza). 



2. The funicle, or non-celluliferous connecting portions of the com- 

 pound fronds, and the barren portions of the stipe [hydrocauhis). 



3. The central disc. 



1. The Radicle, or Initial Point. — In the most simple forms, or those 

 with two stipes, as shown in the figures on Plate iii, there is a slender 

 initial process, which I have termed the radicle. This presents a greater 

 or less development in the different species ; in some being reduced to a 

 mere pustule, or scarcely perceptible point, while in others it attains 

 a quarter of an inch or more in length. Although in none of the species 

 with a single range of cellules does this part show absolute evidence of 

 having been attached to any other substance at the maturity of the fronds, 

 yet it is possible that in the earlier period of its growth, the body may 



