12 



,- >-.--.. 



.* * V V4J.1L' C i;. ^ U.VU t* y?.4. ,,. w v .Vv. 



Echinarachinus excentricus Esch. var. minor 



new var. 

 PI. 2. fig. ?. 



Similar in general to the recent Echi nar ac hinus 

 excentricus from which it differs as follows: size smaller, 

 and test thinner; tumid area in center of abactinal surface 

 absent, the thickness decreasing gradually from the center to 

 the edges which are very thin; excentricity of apical system 

 varies from 1:1 to 1:2.4 and averages 1:2.0, which is 

 somewhat greater than in the living E. excentricus. In this 

 respect the present form is somewhat similar to E. 



which, however, is more excentric, and which has the relative 

 lengths, and the angles between the petals different. 



This variety resembles immature specimens of JE. excen- 

 tricus. Specimens similar to the present form in the Univer- 

 sity of California collection are marked from Burn's Ranch 

 (Santa Clara valley), and from the Tenth Street Well, San Diego. 



