2 ON THE CETACEAN LARYNX. 
The thyroid cartilage is somewhat broad in front, narrower laterally: the 
posterior horn is curved, and is very long and slender: the region of the anterior 
Fig. 1. Larynx oF ForTa GLOBIOCEPHALUS 
(natural size ). E 
The right ala of the thyroid cartilage (7) and part of Part of the same larynx, showing diagrammatically 
the corresponding thyro-arytenoid muscle (th.ar.) have | the insertions of the muscles. cr.ar., crico-arytenoid. 
been cut away. Cr., cricoid. Ar., arytenoid. S.Ar., | i.ar., inter-arytenoid. ¢h.ar., thyro-arytenoid.  art., 
Supra-arytenoid. lig.ar.ep., the aryteno-epiglottidean | articulation of the posterior thyroid cornu with the 
ligament. x, the separate nodule at the extremity of the | cricoid. 
supra-arytenoid cartilage. 
horn is obliquely truncated: the thyroid foramen for the superior laryngeal nerve 
and artery is present. 
The supra-arytenoid cartilages are long and slender. Hach of them sends 
forwards and downwards a long descending horn, which reaches as far as, or a little 
farther than, the anterior apex of the arytenoid: and sends upwards its superior 
horn parallel with its fellow and with the epiglottis, and somewhat overtopped by 
the latter. 
Muscies.—The crico-thyroid muscle springs from a narrow origin at the extremity 
of the horn of the cricoid. cartilage, and, expanding fan-wise, goes to be inserted into 
an extended line on the inferior border of the thyroid and its posterior cornu. 
Figs. 3 and 4. 
Parts of the same larynx from the front and from the left side, chiefly to show the crico-thyroid muscle (cr.th.). 
cer.ar., cerato-arytenoid muscle. th.hy., origin of the thyro-hyoid muscle. s/.th., insertion of the sterno-thyroid 
muscle. 'r., trachea. 
