10 



ecor 



Figure 7- Structure of m. subcoraco- 

 scapularis in various lizard 

 families 



A - Scincidae (Mabuya sp) ; coracoid 

 head of muscle very large. B - 

 Lacertidae (Eremias arguta); with the 

 disappearance of "epicoracoid" the 

 coracoid head divided into two parts. 

 C - Gekkonidae (Gekko gecko); 

 scapular part of coracoid head 

 completely reduced; also absence of 

 lig. axillaris. D - Agamidae 

 (Phrynocephalus mystaceus ) ; scapular 

 part of coracoid head very well 

 developed; origin migrated further 

 back, up to the scapular head proper 

 of m. subcoracoscapularis , from 

 which it is separated only by lig. 

 sternoscapularis interniun; cor - 

 coracoid head of m. subcoraco- 

 scapularis. Other symbols same as 

 Fig. 3 and h. 



evolve in the same direction in all Scincogekkonomorpha. Perhaps, this 

 indicates that gekkonids, scincids, and lacertids, until their divergence 

 into separate families, subfamilies and sections, evolved for a long time 

 (possibly from Upper Jurassic to Upper Cretaceous) in the same Scinco- 

 gekkonomorphic lineage. 



It is in gekkonids, scincids, and lacertids that we note complex forma- 

 tions such as the crossing of muscle fibers in the mm. pubo-ischio-femoralis 

 internus et externus (Sukhanov, 1957). Still small in Gekko gecko, the m. 

 ext . iliotibialis has enlarged; the m. fl tibialis internus I is divided into 

 several heads (not yet separated in Gekko and Eumeces , two heads in Lacerta 

 agilis , three in L. lepida, four in Teratoscincus and Cyrtodactylus ) . 



The changes in the m. subcoracoscapularis are extremely significant. In 

 the scincids, the coracoid head of the muscle is very large (Fig. 7, A); it 

 originates from the inner side of the coracoid, the "epicoracoid," and the 

 scapula. This continuous muscle layer is triangular in shape and is sepa- 

 rated from the scapular head by the lig. sterno-scapularis internum. The 

 scapular head is relatively small and its fibers do not reach the outer side 

 of the scapula. In the lacertids (Fig. 7, B) the coracoid head is divided 

 into two parts - the scapular, partially reduced, and the coracoid. The 

 scapular part has complete disappearance in gekkonids (Fig. 7, C). There is 

 also partial reduction of the coracoid part proper from lacertids to 

 gekkonids (origin of muscle occupies only the bony part of the coracoid). In 

 the agamids studied, separation of the coracoid head into two parts was also 

 noted but only the coracoid part is relatively reduced in size. The scapular 

 part is, apparently enlarged and forms the anterior inner scapular head of 

 the m. subcoracoscapularis (Fig. 6, D). In the Iguanomorpha, there is also a 



