NEPHROTOMIC PLiTE 

 EPITHELIAL CORE / (MESOMERE 



DMITF 



PRONEPHRIC DUCT 



HYPOMERIC ■ 

 MESODERMA 

 CONTRIBUTIO 

 TO LiTERA 

 BOOT WALL 



CONTRIBUTION 

 FROM SPLANCHNIC 

 LAYER OF HYPOMERE 



Fig. 252. Mesodermal contributions to developing body. (A-D) Sections through 

 developing chick of 48-52 hrs. of incubation. (A) Section through somites of caudal 

 trunk area showing primitive area of mesoderm and coelomic spaces. (B) Section 

 through anterior trunk area depicting early differentiation of somite. (C) Section 

 through trunk area posterior to heart revealing later stage of somite differentiation than 

 that shown in B. (D) Section through developing heart area. Observe dermomyotome, 

 sclerotomic mesenchyme, and mesenchymal contributions of hypomere to forming body 

 substance. (E) Mesodermal contributions to anterior end of developing embryo of 

 Ambystoma of about 19 somites. (Redrawn and modified from Adelmann: 1932, J. 

 Morphol. 54.) (F) Frontal section of early post-hatching larva of Rana pipiens show- 

 ing mass of mesoderm lying between gut, epidermal and neural tubes, together with the 

 contributions of the mesoderm to the visceral arches. 



524 



