160 



GCELBNTERATA. 



like spreading and branched growths, which are furnished 

 with a strong footstalk (fig. 51). In all probability the 

 organism was attached by the base of the footstalk to some 

 foreign body, but no actual demonstration of this has as yet 

 been obtained. The branchlets carry upon one side a series 

 of little chitinous cups or " cellules," each of which must have 

 contained a polypite, and which agree with the similar struc- 



Fig. 51. Dcndrog raptus Hallianus. a, Portion of the frond, natural size ; b, Portion of a 

 branch, enlarged ; c, The footstalk and some of the principal branches, natural size. (After 

 Hall.) 



tures of ttte Graptolites in partially overlapping one another ; 

 thus differing from the " hydrotheceB " of the Sertularians. 



In Dictyonema (fig. 52) we have ' organisms resembling 

 Dendrograptus in many respects, but not possessing any foot- 

 stalk. The frond is branched and plant-like, and is fan- 

 shaped or funnel-shaped in form. It is not certainly known 

 whether the organism was attached by its base or not ; but 

 there is the strongest probability in favour of its having been 

 fixed. The branches radiate from the base, running nearly 

 parallel with one another, and often bifurcating. They are 

 united to one another at short intervals by numerous, 

 irregular, slender, transverse processes or dissepiments, and 

 they bear small horny cups or " cellules " like those of the 



