STUDY OF THE GRAPTOLITES. 187 



have been temporarily attached at this point to the sea-bottom or to some 

 other object ; though all the evidence is opposed to this view. 



In some of the bi-celluliferous forms, and probably in all of them, there 

 is a somewhat similar extension below the base of the celluliferous portion 

 of the stipe, though it is usually more slender ; but whether tliis is always 

 the true initial point of the whole body, or whether it is only the broken 

 point of attachment to a frond, may sometimes admit of doubt. It is con- 

 spicuous in PhyllograptuH typus ; and we observe this feature also in 

 Retiograptus ; but in one species of this we learn that it is only a broken 

 process of attachment of the individual stipe by its solid axis, 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 (PL iv, fig. 9). 



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

 initial point or radicle is in fact the commencement of the solid axin, 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 oppo- 

 site 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 Funicle. — 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 always destitute of cellules; and this, with its divisions, I have 

 termed the funicle. 



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 com- 

 pound forms, which is barren or non-celluliferous (the hydrocaulus). It is 

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

 as G. logani, that the celluliferous parts of the true stipes commence. 

 ' In one of the proper branching forms, however, the cellules begin 

 immediately beyond the first subdivisions of the funicle, as in the four- 

 stiped species (fig. 29). 



