3 i6 



ELEMENTARY ANATOMY. 



[LESS. 



cornua. Thus we may have I. Muscles connecting the 

 hyoidean and branchial arches (e.g. the cerato-hyoideus ex- 

 ternus and interims). 2. Muscles connecting the branchial 

 arches of each side (e.g. the constrictores arcuum of Meno- 

 branchus. 3. Muscles suspending the branchial arches to the 

 parts above them as the levatores arcuum of Menobranchus. 

 The conditions of man's sterno-hyoid are very generally 

 present, but the muscle may be wanting, as in Chelonians, or 



FIG. 286. SUPERFICIAL MUSCLES OF RIGHT SIDE AND OF EXTENSOR SURFACE 

 OF RIGHT PECTORAL LIMB OF MENOBRANCHUS. 



AB, adductor branchiarum ; B, biceps ; CP, constrictor pharyn-gis; CHE, cerato- 

 hyoideus externus ; D, deltoid ; Di, first part of digastric ; EB, extensor 

 brevis ; EL, extensor longus; ExO t external oblique; LA, levatores 

 arcuum; LA 1 , first part of the same; LD, latissimus dorsi ; M, masseter ; 

 MH 2 , mylo-hyoideus posterior ; OH, omo-hyoid ; S, subclavius ; SL I and 

 SL 2 , supinator longus; T, temporalis ; Tz, trapezius ; T 2 , triceps; U, 

 ulnaris. 



arise as far back as the xiphoid, as in the Ant-eaters. It 

 may unite with its fellow to form a thick azygos muscle, as 

 in the Dolphin, or arise from the anterior ribs and be inserted 

 into the mandible as well as into the cornua, as in Serpents. 

 It may also form part of a great muscular mass passing un- 

 interruptedly from the pelvis to the hyoid, as in Menobran- 

 chus, and thus we see that it enters into the composition of 

 that part of each great lateral muscle which in Fishes is 

 inserted into the median portion of the hyoidean arch. 



A separate sterno-thyroid and a distinct thyro-hyoid are 

 structures peculiar to man's class. The former blends with the 



