TllITICELLA FLAVA. 543 



the peduncle, wliicli by their contractions produce very 

 remarkable nodding movements in the cell'^. 



Some of the species are furnished with a semicircular 

 chitinous band or rib, which passes upward from the 

 dorsal surface on each side towards the aperture, and 

 may serve to strengthen the wall of the cell. Sars has 

 named it frenaculwn. I have not included the character 

 in the generic diagnosis, as it does not seem to have any 

 special significance, and is wanting in a form which in all 

 the most important points agrees with Triticella. 



Dalyell was the first (1858) to describe a member of 

 the present genus; but his brief account of Triticella 

 flava gives no true idea of its structure. The peculiari- 

 ties of the generic type were really unknown until the 

 publication (in 1873) of a most able paper by G. O. 

 Sars, on certain Scandinavian species of Triticella, in 

 which he has fully demonstrated its structure and dis- 

 cussed its affinities and systematic position f. 



Triticella flava, Dalvell. 



Plate LXXX. fig. 7. 



Triticei.la flava, Daly. Eem. An. ii. GO, pi. xix. fig. 1 : G. 0. Sars, Chris- 

 tian. Videusb. Selsk. Forhand. 1873, 398. 



Zocecia of a faint yellowish colour, short ovate (viewed 

 laterally), the dorsal surface curved outwards; pe- 

 duncle very short, about half the length of the cell. 



Polypide with 20 tentacles. 



* 'Bryozoaires des cotes de France,' p. 101. 



t " Oiu en hidtil lidct kjendt moerkelig Sljegstype af Polyzoer," af G. O. 

 Sars. 



