IV 



MUSCLE-BUDS 



207 



during development. According to Mollier (1893) and Braus (1899) 

 such a process actually occurs. Broad anastomoses or bridges make 

 their appearance connecting the various radial muscle rudiments 



2r 22 23 24 25 26-27 28 £££££'^£1^ 



J7J8 29 30 31 32 33 34.3536 37_3839^0.4r 



B 



18 19 20 



2T 22 23 24 25 2627j^^^^34 35 



25 26 



22 23 24 J^JL. 2 *.-™^! .U 32 33 34 



Fig. 114. — Illustratiug the muscularization of the pelvic iin in Spinax. 

 (After Braus, 1899.) 



A, 20 mm. (70 mesoderm segts.) ; B, 25 mm. (74 m.s.) ; C. 20 mm. ; D, 32 mm. The myotomes are 

 indicated by Arabic numerals. The muscle-buds are shown in black, those within the fin rudiment 

 being numbered with Roman numerals. The nerve-trunks are shown with double contour. 



with their neighbours near their proximal ends. These connecting 

 bridges persist for a short time and then disappear. According 

 to the authors mentioned they are the expression of a cellular 

 interchange taking place between neighbouring muscle rudiments. 



