SARSIELLA — KORNICKER 



9 



verse striations and extending outward in unstriated lamellar prolonga- 

 tion with fine marginal fringe along anterior and posterior parts on 

 some specimens (figs. 4c, g). Hinge simple, occupying posterior two- 

 thirds of dorsal margins (fig. 4a) and connected by ligament (pi. la, b). 



Figure 2. — Sarsiella zostericola Cushman: comparison of lateral outlines of instars III-V 

 and adults (females on left, males on right). 



Outer lamella of valve laminated (pi. Ic-J) ; dupHcature in x-section 

 appearing as fold in inner part of outer lamella (pi. Id) ; marginal ridge 

 (pi. \d) and medial ridge (pi. le) in x-section appearing as fold in 

 outer part of outer lamella. Clusters of dorsally oriented spines 



