134 PROFESSOR OWEN ON THE ANATOMY OF 



maxillary : it is a thin muscular layer, eight lines in breadth, inserted into the tendon 

 of the retractor anguli oris, and partly continuous with a thicker layer of the same 

 sphincter which passes round, beneath the mouth, closely connected with the skin of 

 the lip, to the same tendon of the opposite side. A small oblique tendon is developed 

 near where the fibres of the longitudinal muscle {dermolabialis anticus, s) blend with and 

 are lost in the orhicidaris oris. 



The accessorius ad orbicularem oris {ih. r) arises from the maxillary behind the 

 muscle it assists, and contracts as it descends and blends its fibres with the true orbi- 

 cularis : it receives the insertion of the dermolabialis posticus. 



The buccinator {ib. u) is of unusual longitudinal extent, and consists of a thin layer 

 of flattened fasciculi of vertical fibres arising from an aponeurosis attached to the tooth- 

 less border of the upper jaw, and inserted at the outside of the similar border' of the 

 lower jaw. 



A small mass of labial glands, two inches in longitudinal extent and from two to 

 three lines in breadth, rests upon the under and fore part of the buccinator and dips 

 under the orbicularis oris. 



The levator auricula {ib. v, v') has an extent of origin from the epicranial fascia of 

 nearly four inches. The most anterior fasciculus, v, comes off behind the eye and is a 

 protractor : the posterior fasciculus, v', arises from the occiput and is a retractor : these 

 with the intermediate fasciculi acting in succession would rotate the ear. Beneath the 

 posterior fasciculus is a deeper-seated retractor of the ear inserted into the inferior and 

 outer part of the auricular cartilage. 



The depressor auricula {ib. w) is a roundish, slender muscle, which arises from the 

 angle of the jaw, penetrates the parotid gland, and is inserted into the lower part of the 

 cartilage of the ear. 



Cuvier and Duvernoy long ago pointed out that the protraction and retraction of the 

 tongue of the Anteaters and Echidna were not due to any peculiar conformation of the 

 hyoid bone and muscles, but to another mechanism answering the same end. Those 

 distinguished anatomists seem, however, not to have noticed to what an extent the base 

 of the tongue is removed from the basihyal, nor to have recognized the share which the 

 genioglossus takes in the formation of the tongue itself. "The hyoid in the Myrme- 

 cophar/te (the species is not noted) is placed very far back, and as a consequence, the 

 base of the tongue is placed equally far back, although it is not, so to speak, attached 

 to the hyoid bone. It seems to be composed exclusively of the sternoglossi and of an 

 annular muscle'." 



The gular fasciculi of the genioglossus are recognized as 'geniobuccales,' and are 

 described as " diverging upon the sides of the base of the tongue, beyond which they 



' " L'os hyoide etoit place tres en arrifere ; il en resulte que la base de la langue est egalement tr&s en sirriere, 

 quoique celle-ci ne tienne pas, pour ainsi dire, k l'os hyoide." — " EUe ne semble compos^e que des sternoglosses 

 et d'un muscle annulaire." — Lemons d'Anatomie Comparee, torn. iii. 1799, p. 265. 



