DISCOVERY REPORTS 



B n 





B b 



Text-fig. 43. The development of the body muscles, gill filaments and brain of (a, a', a") Maurolicus muelleri; (B b , B bb ) 

 Cyclothone braueri, and (b, B m , B bm ) C. microdon. In A and B, which are transverse sections through the body just in front 

 of the caudal peduncle, the muscle fibres are shown in black and are drawn to scale. The drawings of the gill filaments 

 are from the lower part of the first gill arch, fb, forebrain; mb, midbrain; cb, cerebellum, (a, b, x 15; a', B m , B b , X20; 

 a", B bb , B bm , x 9.) 



