INTERNAL SECRETIONS 



513 





zym. 



cap. ' 



Ud. c. 



I... 



":*>'- 



v ;, - 



**,:-.* <?" 



^ o o o , o 



f 



^ -AiaS ^ 



zym. 



FIG. 243. IsLsr o? LYNJERHANS FRO.M SPLENIC END OF PANCREAS OF DOG. 

 (Vincent and Thompson, drawn by Mrs. F. D. Thompson.) 



bid. c., Rsd blood-corpuscles; c.a.c., central aciriar cells of pancreas proper; cap., 

 blood capillaries; i., islet of Langerhans; 1., lumen; trans, c., transitional cells; 

 zym., zymogenous tissue. 



for. caec. 

 raphe of tongue 

 hyoid (2nd & 3rd arches) 



susp. ligament 

 thyr. cart (4th & 5th arches 

 sup. parathyr. 

 -from 4th cleft 

 inf. parathyr. 

 thymic strand 



thymus (3rd deft) 



FIG. 249. DIAGRAM SHOWING DEVELOPMENT OF THE THYROID AND THYMTTS. (Keith.) 



The three parts of the thyroid body are indicated by a stippled lire; the position 

 of the parathyroids on the posterior aspect of the lateral parts is indicated. 



33 



