288 University of California Publications. [Zoology 



gradually in a regular curve, approximately 30° from the axis, 

 increasing- the diameter about 20%. The aboral margin is per- 

 fectly smooth but the oral is deeply and regularly incised, form- 

 ing a serrate margin of twenty erect, acute teeth. 



The wall is unusually thin and hyaline even for this thin- 

 walled genus and shows only the faintest traces of structure. 



The animal has not been found in the lorica. 



The number of adoral ciliary plates in the genus Tintinnus 

 is stated by Daday ('87) to be 18-20. There are 20 eireumoral 

 teeth in the lorica of this species, a fact which indicates that 

 there is some correlation between the structure of the adoral 

 apparatus and the formation of the serrate oral margin of the 

 lorica. 



This species belongs to the form-cycle of T. fraknoi Daday, 

 differing from it in the possession of the serrated eireumoral 

 margin of the lorica. and in attaining less than one half its 

 size. As figured by Daday ('87) the ends in T. fraknoi flare 

 more gradually and are less differentiated than in T. serial us. 

 In the Pacific plankton, however, I find that T. fraknoi gen- 

 erally has the Mare better developed than it is in Daday 's 

 figures of the species from the Mediterranean. 



Dimensions: — Length, 150 /it; diameter inside of flare, an- 

 teriorly 18 //., posteriorly 12/*; of oral opening, 25 /a ; of aboral, 

 15 ft; length of teeth, -4 /a. 



Taken in the plankton at the surface inside the kelp belt off 

 San Diego in June. The structure of the lorica indicates a 

 eupelagic distribution. 



Tintinnopsis reflexa sp. no v. 



PI. XXVI. Fig. 2. 

 The lorica of this organism is cylindrical, finger-shaped, its 

 length two and one-half times its diameter, with rounded fundus 

 and reflexed oral rim. The sides are straight and at the mouth 

 the wall is reflexed, forming a broadly rounded oral perimeter. 

 and continues aborally parallel to and outside of the cylinder 

 for one-tenth of its length, terminating in a smooth unmodified 

 edge. The wall is thin, translucent and has the primary reticu- 

 lations described by Biedermann ('93) and Brandt ('96) but 



