Eobert Bennett Bean 



307 



and internal mannnary arteries rise from I'art I ; the inferior thyroid, 

 suprascapular and transverse cervical arteries rise from a common trunk 

 which comes from Part I, and is known as the tliyroid axis; the super- 

 ficial cervical artery is absent, its place being taken by small branches 

 from the transverse cervical artery; the ascending cervical artery rises 

 from the inferior thyroid artery, as it does in practically all the cases of 

 all the types; and the costo-cervical trunk rises from Part II. The 

 internal mammary artery rises from the thyroid axis five times in this 

 type — four times in infants — showing a bunching of the branches. 



ACP 



C.T. 

 KKTt 



RD.T.C. 



ATS. 



Fig. 4. Type III, occurring in 22^ of the specimens. For index to lettering see 

 Fig. 1. 



There are in this type 18 male negro subjects, 2 female negro 

 subjects, 3 male white subjects, 1 female white subject, and 1 subject in 

 which the sex and race are not determined. Types I andll are the rep- 

 resentative types for the right and left sides of the body respectively. 

 Cf. Fig. 7, A and B, pp. 314 and 315. 



Type III (Fig. 4) with slight variations occurs in 22% of the cases 

 classified, 25 times in all, 13 on the right side of the body and 12 on the 

 left side. The vertebral and internal mammary arteries, and the costo- 

 cervical trunk rise from Part I in this type and in the two remaining 



