2a. Main externalized bone of priapium a toxactinium that curves to right or to left under
head of male (Fig. 2); large, fleshy, smooth, or ruffled seminal papilla (Fig. 2); translucent,
membranous dome on dorsal surface of head ........................ 3
2b. Main externalized bone of priapium a ctenactinium; seminal papilla small; no translucent,
membranous dome on dorsal surface of head . . . . . . . . . . . . . . . . . . . . Neostethus