Biol. Pl. tractella. [mod.L., f. L. tract-, ppl. stem of trahĕre to draw, after FLAGELLUM: cf. PULSELLUM.] The anterior flagellum of an infusorian, etc., which serves to draw the body after it in swimming. Hence Tractellate a. [-ATE2], furnished with a tractellum.
1880. Kent, Infusoria, I. 429. Among the free-swimming monoflagellate Infusoria…, where the locomotive appendage … fulfils during natation the role of a tractellum.
1891. Cent. Dict., Tractellate.
