STUDY OF THE GRAPTOLITES. 217 



which existed as one of the members of the entire frond, the true initial 

 point of which would be in the centre of the whole (Plate iv, fig. 9). 



In all the forms of Graptolitidse which appear to have been free, the 

 initial point or radicle is in fact the commencement of the solid axis, 

 which will be noticed farther on. In those Graptolites with two simple 

 stipes, the little radicle-like process enlarges above, and the stipes, 

 diverging in opposite directions, are closely united at their bases, and 

 the cellules often begin almost in the axil between the two (Plate iii, 

 and figs. 1 and 2, page 173). 



2. THE FTJUICLE. 



In the Graptolites with four stipes, the condition appears like that 

 of two individuals of the two-stiped forms, conjoined by a straight 

 connecting process of greater or less extent, with the initial point in 

 the centre, though often obscurely marked. This connecting process 

 is ahvays destitute of cellules; and this, with its divisions, I have termed 

 the fiinicle. 



In those forms with eight stipes, the funicle is twice divided at its two 

 extremities; and where there is a greater number of simple stipes, it is 

 correspondingly subdivided. Neither the central portion, nor any of its 

 subdivisions, become celluliferous ; and there is usually more or less of the 

 stipe above these subdivisions, both in the simple as well as the compound 

 forms, which is barren or non-celluliferous (the hydrocaidus'). It is only 

 beyond the last subdivisions of this part of the body, in such forms as 

 G-ra-ptolitlius logani, that the cellulifer- j.jg_ 29. 



ous parts of the true stipes commence. 

 In one of the proper branching forms, 

 however, the cellules begin immedi- 

 ately beyond the first subdivisions 

 of the funicle, as in the four-stiped 

 species {Graptolitlius milesi, fig. 29). 



These barren or non-celluliferous 

 portions of the graptolitic body, are not 

 otherwise essentially different from 

 other parts of the stipe. In the absence of cellules, they are conse- 

 quently more cylindrical, and apparently more solid, as if the test were 

 thicker and the interior canal less developed than in the other parts of 

 its extent. 



Cab. Nat. 28 



