STUDY ON THE ANATOMY AND HISTOLOGY OF UPPER RESPIRATORY TRACT OF LIPOTES VEXILLIFER MILLER

The present paper deals with the anatomy and some histology of the upper respira-tory tract of Lipotes. The observation shows that Lipotes possesses vestibular sacs,nasofrontal sacs and premaxillary sacs. The three pairs of air sacs are all larger in theright side than those in the left, and right vestibular sac is the largest. Accessory sacand connectng sacs are lacking. Under subcutaneous fat tissue of the head, a pair of "floating bones" are situatedin both sides of the nasal passage. They are compact connective tissue composedof irregular collagenous fibers. Capillaries and many fatty vacuoles are distributed inthe surrounding tissue. The larynx of Lipotes which consists of thyroid, epiglottis and cricoid cartilages, anda pair of arytenoid cartilages, and which does not differ from that of other Platanistidae.Plicae (false vocal cords) are present in the tissue of larynx.