The caudal peduncle is expanded laterally into strong keels. These grow on a pedicel or peduncle. The sides of the caudal peduncle are expanded into prominent lateral keels. The anterior portion of the body is deep, gradually tapering into a slender caudal peduncle. The peduncle of the caudal fin is thick. The flowers are arranged in a dense spherical inflorescence in diameter on a short peduncle. There are six bracts in a whorl below the peduncle. The ventral spinocerebellar tract then enters the cerebellum via the superior cerebellar peduncle. Some species also have recurved spines on the base of the tail ("caudal peduncle"). The term can also mean the lower bract on a peduncle. The damage to the cerebellum or the inferior cerebellar peduncle can cause ataxia. Behaviors include breaching, spyhopping, lob-tailing, tail-slapping, pectoral fin-slapping, peduncle throws, charging and parrying. Cranial nerve 4 (trochlear nerve) wraps around the lowest part of the cerebral peduncle. The peduncle (the primary flower stalk) can be long or short. The corticobulbar and corticospinal fibers are found in the middle third of the cerebral peduncle.