234 



SERTULARIIDJE. 



Fig. 28. 



S. fusiformis (Hincks). 



S. temtta (Aider). 



Genus SERTULARELLA, Gray. 



Der. Diminutive of Sertularia. 



SBRTULARIA aucfc. (in part). 



COTULINA, Agassiz, N.H. United States, iv. 356 (for 8. polyzonias only). 



AMPHITKOCHA, Agassiz, ibid. iv. 356 (for S. rugosa). 



GENERIC CHARACTER. Zoophyte plant-like; stem more 

 or less branching, jointed, rooted by a creeping stolon ; hy- 

 drothecae biserial, decidedly alternate, with a toothed orifice, 

 and an opercidum composed of several pieces ; gonothecte scat- 

 tered, transversely ringed, slightly dissimilar in the two sexes. 



THE genus Sertularella was constituted by Gray, to in- 

 clude that Section of the Sertularice of which S.polyzonias 

 may be regarded as the type. Only two British species 

 had been recognized at the time of the publication of his 

 list ; but the number has since been increased to six. In 

 other parts of the world the group is largely represented ; 

 and the examination of many foreign forms has led me to 

 retain the genus. The decidedly alternate arrangement 



