tall

[A. S. tog/.] I. Cauda, the posterior free extremity of the spinal column in an animal. 2. Any tail-like structure, t. bone, coccyx, t. fold, an embryonic fold in which is developed the t. gut. t. gut, the portion of the archenteron in the caudal extremity of the embryo, t. sheath, the protoplasmic envelope of the tail of a spermatozoon.