154 ANATOMY OF VERTEBRATES. 



its junction with the basihyal. In some birds it divides into three 

 or more portions : the iiosterior descends obliquely forward, and 

 is inserted into the tendinous commissure of the mylohyoideus : 

 the middle portion is inserted into the urohyal : the anterior fas- 

 ciculus is inserted into the side of the basihyal above the trans- 

 verse hyoglossus. The actions of these different portions vary 

 according to their insertion ; the first and second depress the apex 

 of the tongue by raising the urohyal, the third raises the tongue 

 and draws it to one side Avhen it acts singly. 



3rd. The Genio-hyoideus, fig. 76, Z> : this arises by two fleshy 

 bands from the lower and internal edge of the lower jaw ; these 

 unite, pass backward, and surround the cornua (thyrohyals) ; and 

 as they draw them forward protrude the tongue from the beak. 



4th. The Cerato-hyoideus : this passes from the thyrohyal to 

 the urohyal, and is therefore subservient to the lateral move- 

 ments of the tongue. 



5th. The Sterno-hyoidei: these are replaced by a slip of 

 muscle which extends from the anterior surface of the upper 

 larynx to be attached to the base of the glossohyal. 



6th. A small and short muscle, which is single or azygos ; it 

 passes from the basihyal to the under part of the glossohyal ; it 

 depresses the tip of the tongue and elevates its base. 



7th. A short muscle, fig. 75, c, which arises from the junction 

 of the basihyal with the urohyal, and is inserted into the thyro- 

 hyal. ^ 



All these muscles are remarkably large in the Woodpecker, in 

 which there is a singular pair of muscles that may be termed 

 Cerato-traclieales (fig. 77, h). They arise from the trachea 

 about eight lines from the upper larynx, twist four times spirally 

 round the trachea, and then pass forward to be inserted into the 

 base of the thyrohyals. This is the principal retractor of the 

 singular tongue in this species. 



§ 147. Salivary Glands. — The salivary organs, being in general 

 developed in a degree corresponding to the extent of the changes 

 which the food undergoes in the mouth, and the length of time 

 during which it is there detained, are by no means so conspicuous 

 a part of the digestive system in Birds as in Mammals. Glands 

 which pour out their secretion upon the food prior to deglutition 

 are, however, met with in every bird, but vary in number, position, 

 and complexity of structure. 



In some species, as the Crow, they are of the simplest struc- 

 ture, consisting of a series of unbranched, cone-shaped follicles or 

 • Dr. Salter proposes the name of ' Cerato-glossal ' for this muscle, ccxl-. p. 1 140. 



