Figure 3. The development and differentiation of the m. trapezius and 

 m. episterno-cleido-mastoideus in various lizards 



A - Teratoscincus scincus , almost no traces of differentiation of either 

 muscle. B - Eremias arguta: in m. trapezius division into two parts - 

 one whose fibers are attached to the acromial part of the scapula and the 

 second to the clavicle. C - Eremias grammica: both parts of m. trapezius 

 well separated; the more cranial section of the posterior part (m. acromio- 

 trapezius) has lost muscle fibers and become aponeurotic. D - Phrynocephalus 

 mystaceus: m. episterno-cleido-mastoideus completely divided from m. 

 trapezius, which in turn is divided into two independent parts - m. acromio- 

 trapezius and m. clavotrapezius . E - Phyrnocephalus interscapularis : 

 reduction noted in m. clavotrapezius. F - Phrynocephalus helioscopus : m. 

 clavotrapezius has completely lost its muscle fibers, replaced by apo- 

 neurosis, atr - m. acromiotrapezius ; ctr - m. clavotrapezius, ecm - m. ' ■ 

 episterno-rcleido-mastoideus , tr - m, trapezius. 



