PROC US NAT MUS VOL. 122 



KORNICKER PLATE I 



Sarsiella zoslericola Cuslunaii, transverse sections through shell: «, elorsal, throu^'h liin.^e 

 and litjament; /;, enlaruenient (jI Hi;anient in a: c, outer lamella showing lineations, inner 

 side ot lamella is toward bottom of illustration; i/, \-ential margin, left \al\c; 

 t\ middle ridge;/, ventral margin right valve showing selvage, false marginal pore canal 

 with bristle, marginal ridge. (Same scale in microns: a, f; b-e.) 



