STUDY OF THE GRAPTOLITES. 



181 



Tn G. ramosus, as slio\Yn in the following figure, and also in fig. 18 of 

 Plate ii, the lower part of the stipe, for a considerable distance, has a 

 range of cellules on each side, parallel witli the axis; and becoming bifur- 

 cate above, it presents two stipes or branches, each with a single range of 

 cellules. All the species of this group have a peculiarity in the form of 

 the cellules, which will be noticed hereafter. 



Fig. 21. 



Gkaptolithus (Dicraxograptus) ramosus. 



These species, in their mode of growth alone, present forms which might 

 be regarded as intermediate between the monoprionidian and diprionidian 

 groups; tliough the typical forms, G. pristis and allied species, never show 

 any tendency to a division of the parts of the stipe ; and we shall observe, 

 as we progress, that these forms are connected with other differences of 

 structure. 



