138 



Fig. Ul. Sertulare'.la tridentata (Lmx.). 

 Ganze Kolonie in nat. Größe. (I. Fig. 46.) 



This species is very elegant; 

 the specimens were collected in July, 

 but unfortunately there are no repro- 

 ductive bodies; the peri.sarc is com- 

 paratively weakly developed for the 

 large size of the colony. 



The joints are irregulär, but 

 when exaniined closely there are 

 found indistinct transver.se gfrooves 

 giving rise to joints (Inaba Fig. 48 

 = hier Fig. 113), each bearing three 

 liydrothecae. The coalescence of 

 the hydrothecae with the steni is 

 u.sually regarded as a characteristic 

 of the genus Thuiaria. but this 

 alone is not sufficient to distin- 

 guish it froni other genera; hence 

 Allman has pointed out the irregu- 

 larity of the joints, which, however, 

 is again inadequate. According to 

 W. M. Bale the difference of Thuiaria 

 and Sertularia is as foilows; in Ser- 

 tularia the hydrothecae are oppo- 

 site, while in Thuiaria they are 

 arranged on either side of the stem 

 and there is no fixed relation be- 

 tween thenienibers ofthe two rows. 

 Hence in Sertularia each Joint al- 

 ways bears an even number of hydi o- 

 thecae, while in Thuiaria there may 

 be three, four, five or six. In my 

 specimens there are three hydro- 

 thecae to each Joint: following Bale 

 I have referred it to Thuiaria." 

 (Inaba 1890.) 



Fig. 112. S. tridentata (Lmx.). Stammstüek. (I. Fig. 47.; 



Fig. 113. S. tridentata (Lmx.). 

 Hydrotheken. (I. Fig. 48.) 



