Journal of morphology . It would seem,then, that we have in the temporarily rigid cilium of Stentoran organ which is virtually a cilium, but having acquiredenhanced tactile sense (probably possessed in some degree byall cilia), and the power of becoming rigid, is already on itsway to become a specialized organ of touch. 488 JOHNSON. [Vol. VIII. 3. Pharyngeal Funnel. That portion of the frontal field that sinks spirally into theanimal was regarded by Stein and later writers as theoesophagus, and its external aperture as the mouth. ButSchubcrg (90, p. 202) has shown conclusively that the wholefu
Journal of morphology . It would seem,then, that we have in the temporarily rigid cilium of Stentoran organ which is virtually a cilium, but having acquiredenhanced tactile sense (probably possessed in some degree byall cilia), and the power of becoming rigid, is already on itsway to become a specialized organ of touch. 488 JOHNSON. [Vol. VIII. 3. Pharyngeal Funnel. That portion of the frontal field that sinks spirally into theanimal was regarded by Stein and later writers as theoesophagus, and its external aperture as the mouth. ButSchubcrg (90, p. 202) has shown conclusively that the wholefunnel is an in-turned portion of the frontal field, and thatthe real mouth lies at its innermost extremity (Figs. 35, 62, 0).Schuberg has very accurately figured (Taf. XIV, Figs. 2, 3)the appearance of the pharyngeal funnel of 5. cceruleus in thecontracted state. With the extension of the animal, thefunnel undergoes great enlargement, and the outer turn, orbuccal pouch (Figs. I, 33, 62, ) ( Peristomtasche of Stein). fig- I- — Diagram of frontal field and pharynx uf 6. cceruleus, z., adoral zone ; , buccal fold ; , buccal pouch ; //?. pharynx ; vel., velum. sometimes attains nearly one-half the area of the whole frontalfield. It serves as a very capacious hopper for whatevergrist is brought by the alimentary vortex. If one looksdirectly down upon the frontal field, the buccal pouch is seento have an outline varying from almost circular in state ofutmost expansion, to reniform and crescentic according to theamount of distension (Fig. I, ). It also varies much indifferent individuals. The concave side of the crescent isalways dorsal; the convex outline is formed by the hypostom of Stein. This hypostom is the thin raised edge of theventral body-wall, crowned with the adoral zone as it passestowards the right to enter the funnel. Inasmuch as the name No. 3.] MORPHOLOGY OF THE STENTORS. 489 hypostom is based upon the wrong assumption that themouth is
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