4 MR. C. TATE REGAN ON THE 



3. Structure of Male JSTbostethus lankesteri. 

 a. External Characters. 



The male differs from the female externally in the presence of 

 the priapium (text-fig. 2), a fleshy appendage that lies below the 



Text-figure 2. 



ctm. ^' 



sp. P- 



Keostetlivs lankesteri, S ■ Head and priapium (X 10). A, proctal side; 

 B, aproctal side. 



ct., ctenactinium ; ctm., ctenactinial muscle; a., anus; r., end of priapial rib ,-■ 

 v.d., terminal coil of vas deferens; pv., pulvinulus ; pva., pulvinular ap- 

 pendage ; s., pulvinular spine ; g., glandular groove ; ef., efferent groove ;: 

 sp., seminal papilla; p., infrasulcar prominence. 



head and the anterior part of the body, to which it is attached 

 for the greater part of its length, only the posterior end being 

 free. Anteriorly the priapium is confiuent with the isthmus ; 



