102 University of California Publications. [Zoology 



KEY TO THE SPECIES OF TEIPOSOLENIA. 



1. Antapical horns balanced, nearly symmetrical 2 



1. Antapical horns asymmetrical, the dorsal one quite oblique 3 



3. Neck uniform anteriorly T. ambulatrix Kofoid* 



3. Neck constricted anteriorly, deflected dorsally T. fatula Kofoid* 



2. Wall of midbody plainly pitted T. truncata 



2. Wall of midbody not pitted 4 



4. Antapical horns arising from antero-lateral angles of pendant mid- 



body 5 



4. Antapical horns arising from postero-lateral angles of midbody 6 



5. Midbody slender, neck not very oblique to its axis T. exilis 



5. Midbody stout, neck oblique to its axis T. ramiciformis 



6. Midbody subtriangular in lateral view, post-margin not strongly con- 



vex, anterior margins convex T. bicornis 



6. Midbody subelliptical in lateral view, post-margin strongly convex 



T. depressa 



6. Midbody trianguar in lateral \-iew, anterior margins concave 



T. longicornis Kofoid* 



Triposolenia truncata sp. no v. 



PI. 10, fig. 5. 



This is the most robust of the eight known species, with stout 

 neck and stout antapical horns somewhat regularly convex out- 

 wardly, with truncate ends bearing at each terminal angle a short 

 spinule. There are no tubercles on the antapicals. The epitheca 

 is concave anteriorly, and the thecal wall is pitted. 



The midbody is laterally compressed, subtriangular in lateral 

 view, Avith the three margins nearly equal in length and nearly 

 equally convex, the convexity of the ventral margin decreasing as 

 it approaches the neck. The posterior margin is often a little 

 longer than either the dorsal or ventral one, and the ventral mar- 

 gin a trifle shorter than the dorsal one. 



The antapicals are symmetrical, their regions of major flexure 

 and their tips being respectively equidistant from the center of 

 the midbody. They are also approximately equal to the anterior 

 projection, but the distance in a direct line from the center of 

 the midbody to tip of the antapicals exceeds that to the most dis- 

 tant portion of the head. If, however, the distance be measured 

 along the axis to the dorsal edge of the transverse list, the length 

 of the anterior process equals that of the posterior ones. This 



* Bull. Mus. Comp. Zool., 1906. 



