THE FOSSIL STALK-F.YED CRUSTACEA 149 



off. Carapace punctate, posterior and posterolateral portions tiiber- 

 culate. Sternum verj^ broad, the plates extended laterally over bases 

 of ambulatory le<2:s. Abdomen of adult female considerably narrower 

 than sternum, divided by two longitudinal furrows into three parts ; 

 middle part crossed transversely on the second to fifth segments, in- 

 clusive, by a high ridge; lateral parts with a large tubercle on the 

 third to fifth segments, that on the fifth segment the largest. 



Chelipeds of female of moderate length, narrow, palm not swollen 

 but widening slightly toward the distal end. Fingers slender, shorter 

 than palm, toothed on prehensile edges, dark color covering almost 

 the distal half, running along either edge but not so far in the middle. 



Measurements. — Female holotype, length of carapace from pos- 

 terior margin to inner base of inner orbital spine ^A.'^ mm. ; width 

 of carapace 51 mm. 



Occurrence. — Washington : Conglomerate on beach just east of first 

 Geodetic Survey mark beyond the first point east of East Twin River; 

 1926; Oligocene series: Nellie M. Tegland, collector. Holotype in 

 University of California. 



Relation. — Differs from M. kaempferi in its greater fronto-orbital 

 distance, smoother carapace, more transverse inner orbital spine. 



