298 University of California Publications. [Zoology 



where the rings are limited to the anterior end. When inter- 

 mittent deposition continues throughout the whole of shell forma- 

 tion, the entire lorica is composed of superposed rings of equal or 

 unequal width as in 0. annulata of Daday ('87) and C. Jislii- 

 laris [Tintinnus fistularis of Moebius('87)]. Jorgensen is prob- 

 ably correct in regarding the latter species as identical with C. 

 helix (Clap, et Lach.) Jorg. in which the structure of the lorica 

 is imperfectly known, but appears from the figure of Claparede 

 and Lachmann ('5S-'59) and the discussion of Jorgensen ('99) 

 to consist of an apical portion, which is formed by a broad band 

 spirally wound, and a superposed oral portion made up of a 

 number of narrower transverse rings. 



"When the deposition of shell material is continuous and at- 

 tended by torsion we may have the spiral type of banded lorica 

 in the anterior end as in C. claparedi of Daday ('87) and the 

 nearly related if not identical C. ehrenbergi var. subannulata of 

 Jorgensen ( '99), or throughout the whole lorica as in C. pseud- 

 annulata of Jorgensen ('00) and in the species here described. 



The type of shell structure in 0. fasciata suggests the slow- 

 rotation of the animal in a constant direction during the deposi- 

 tion of the shell- forming substance (from which the prismatic 

 elements are formed) and the localization and limitation of the 

 region of its extrusion to a single place upon the animal. It 

 seems desirable that all annulate forms of the Tintinnidae should 

 be reinspected carefully for spiral structure. 



It is evident that the spiral structure of the shell is of great 

 importance in assisting in the rotation of this structure during 

 active locomotion of the animal and maintaining it during pas- 

 sive movement through the water, as for example during its 

 sinking, and that with the rotation there comes a corresponding 

 increase in the moleculai friction and that the flotation of the 

 organism is thus facilitated. 



This species is most nearly related to G. helix (Clap, et Lach.) 

 Jorg., from which it differs in its much greater size (length 

 520^.to 150-200/x in ('. helix), and in the greater width of the an- 

 terior bands which are also plainly spiral, while in G. helix they 

 are probably transverse and are very narrow. The proportions 

 of tht two species are also different. C. fasciata is conical, 



