416 SCHULTE, SEI WHALE. 



vented at this point by the transverse lingualis bundles accumulated here in the immediate 

 vicinity of the faucial orifice. Rostrad of the extremity of the fossa between the genioglossi, 

 the ventral surfaces of these muscles are intimately united to the layers composing the wall 

 of the ventral pouch; elsewhere they are in relation to the cavum ventrale. There are no sepa- 

 rate geniohyoidei. 



The hyoglossus is a long cylindrical muscle arising from the ectal surface of the greater 

 cornu and lateral portion of the body of the hyoid, and continued forward to the tip of the 

 tongue. Close to its origin it crosses the transverse fasciculi of the lingualis mentioned above. 

 Immediately rostrad of these its insertion begins, which is into the dorsum of the tongue from 

 this point to its tip. The hypoglossal nerve lies upon the ventral surface of this muscle at its 

 origin, here giving off large branches, which are continued into the interval between the hyo- 

 glossus and genioglossus and are destined for their supply together with that of the lingualis. 

 A small slip passes from the deep surface of the hyoglossus to the caudal border of the trans- 

 verse lingualis band, well laterad at its junction with the palatoglossus. I failed to find the 

 styloglossus. Carte and MacAlister describe it as of small size, fan-shaped and lateral to the 

 other muscles, sending its fasciculi into the caudal third of the tongue. 



The palatoglossus is of moderate size; arising from the caudal margin of the hard palate, 

 it is directed ventrad towards the base of the tongue where it continues with the transverse 

 lingualis. It lies immediately beneath the oral mucous membrane forming a thin transverse 

 sheet, the most mesal fasciculi apparently inserting into the mucosa about the faucial aperture, 

 the more lateral passing beside it reach the side of the depression between the base of the 

 tongue and this aperture and blend with the lingualis, thus forming a sphincter of the fauces. 

 It shows no tendency to radiate rostrad along the side of the tongue. 



The lingualis is of course intimately blended with the other muscles of the tongue. 

 Towards the base it shows a high degree of independence and can be separated from the other 

 muscles as far rostrad as the insertion of the hyoglossus. It there presents itself as a transverse 

 band forming a thick wall to the depression between the fauces and the paired elevations where 

 the tongue begins to rise above the floor of the mouth. Mesad its more superficial fasciculi 

 arise from the deep surface of the aponeurotic expansion of the raphe between the genio-hyoidei. 

 Its caudal portion is continuous with the palatoglossus and is joined by the slip above men- 

 tioned from the deep surface of the hyoglossus. The remainder inserts into the mucous mem- 

 brane of the side and dorsum of the tongue, the most rostral fasciculi inclining forwards beside 

 the hyoglossus. 



Infrahyoid muscles. The sterno-hyoid muscle is a flat band of longitudinal fasciculi aris- 

 ing from the rostral border of the sternum under cover of the sterno-mastoid, and contracting 

 slightly as it is inserted into the caudal border of the body of the hyoid close to the median 

 line. Its mesal border is in contact with that of its antimere. The sterno-mandibularis overlies 

 its latero-caudal portion where it emerges from beneath the sterno-mastoid and derives some 

 fasciculi from its sheath. The sterno-thyroid, covered by the sterno-hyoid, arises from the mar- 

 gin and ental surface of the sternum, and diverging laterad is inserted into the ectal surface of 

 the thyroid cartilage close to its caudal margin. The thyro-hyoid is a small muscle of obliquely 

 transverse position. It arises from the thyroid near its rostral margin, and narrowing has a small 

 insertion upon the caudal margin of the hyoid close to the midline under cover of the sterno-hyoid. 

 The omo-hyoid has but a single belly. It arises from the rostral margin of the scapula near its 



