108 University of California Publications. [Zoology 



From their origin the horns diverge latero-posteriorly, leaving 

 the midbody almost at right angles to its major axis and curving 

 posteriorly within 1.5 altitudes of the midbody from their origin. 

 This major flexure is usually gradual, but may be more or less 

 abrupt. At the level of the posterior third of the midbody the 

 horns have a direction nearly parallel to its major axis and are 

 then slightly incurved while the ends are again slightly out- 

 wardly curved. In the region of the major flexure and below it 

 each horn bears on its outer surface 2-5 low tubercles. 



The anterior process rises from the midbody above the base 

 of the ventral horn in a direction nearly parallel to its ventral 

 margin. Above the pharj^nx the slender, straight, or slightly 

 curved neck is bent dorsally at an angle of about 30°. The region 

 of the flagellar pore is quite protuberant, its dorso-ventral diam- 

 eter being fully twice that of the adjacent neck. The head is 

 capitate, its dorso-ventral diameter being 1.5-2 times the width 

 of the head. The neck is about 0.75 of the total length of the 

 anterior process. The epitheca is convex and the transverse fur- 

 row scarcely impressed. The transverse lists are low, spreading 

 with many fine ribs. The longitudinal lists are salient about the 

 flagellar pore and the left bears a prominent suture spine. 



The thecal wall is hyaline, structureless. A few pores can be 

 found in the ventral sagittal suture of the neck, and in the 

 tubercles of the major flexures. 



The nucleus is lenticular in form, laterally compressed, and 

 lies in the posterior part of the midbody. Chromatophores, few, 

 irregular in form, yellowish green. 



Dimensions : Length, 152-160 fx ; altitude of midbody in main 

 axis, 37-43 fx ; length of anterior process, 56-72 ix ; length of pos- 

 terior horns, 95-140 /x. 



Taken sparingly in vertical hauls from 100 fathoms off San 

 Diego. 



Triposolenia exilis sp. nov. 



PL 17, fig. 8. 



This is a species of the T. ramiciformis type with pendant 

 midbody. It differs from that species in having a narrower mid- 

 body, a less oblique and more curved neck and antapical horns 

 less widely spreading. 



