The leg muscles of the American coot (Fulica americana Gmelin)
The gross anatomy of all the leg muscles of the American coot (Fulica americana Gmelin) is described. These findings differ on a number of points from earlier investigations of gruiform anatomy: the presence of M. iliotrochantericus medius, the presence of two heads and one inserting tendon of M. femorotibialis internus, the presence of M. gastrocnemius pars intermedia, the presence of two heads of M. flexor perforatus digiti II, the presence of M. extensor hallucis longus pars distalis, the belly of M. adductor digiti II extending for most of the tarsometatarsal length, the belly of M. abductor digiti IV confined to the distal half of the tarsometatarsus, the rudimentary presence of M. adductor digiti IV, and the absence of patellae. Unique to F. americana within the few gruiforms that have been studied is a longitudinal division in the superficial side of M. gastrocnemius pars interna. The species has adaptations associated with swimming and diving; the muscles that flex and extend the tarsometatarsus and the third digit are well developed.