506 



FRANK REAGAN 



ABBREVIATIONS 



D.Ao., Dorsal aorta 

 Gl.t., Glandule thyroidicnne 

 Mes.c, Mesodermal ronnootion 

 Ph., Pharynx 



PuL, Pulmonic arch 



Sin.pr., Sinus preacervicalis 



V.Ao., Ventral aorta 



Vd. 3., Ventral diverticulum of third 



Ph. 1., Common pharyngeal lumen of pouch 



glandule thyroidienne and the pre- .3, 4, 5., Third, fourth and fifth aortic 

 pulmonic caecum arches 



D. Ao. 



D. Ao 



Pul. _ 



/^\^ 



Pul.-. 



Figs. 1 to 5 Sagittal sections through t he branchial region of the right side of 

 the 8.6 mm. pig, series no. 78. S of the C. H. Spurgeon collection. X 60. 



Fig. 1 Section through the upper portion of the fifth arch. The section passes 

 through the glandule thyi-oidieune al)out 20^ mcdia-n to its most lateral extremity. 



Fig. 2 Section (40^ median to section 1) through the dorsal lumen of the fifth, 

 and passing through it not far from its middle point. (The prominence on the 

 dorsal portion of the systemic arch is still noticeable.) 



