THE PROSOMATIC SEGMENTS OF AMMOCCETES 293 



which is clearly serially homologous with the other branchial bars, is 

 composed of muco-cartilage, and not of cartilage. If we follow this 

 series of horizontal sections nearer to the origin of the cartilaginous 



Fig. 116. — Horizontal Section through the Anterior Part of Ammocoetes, 



IMMEDIATELY YeNTRALLY TO THE AUDITORY CAPSULE. 



s/.-,-sA- 5) skeletal bars; m y -m s , striated visceral muscles; mt^-mt^ tubular muscles; 

 b)\-br 3 , brancbiee ; ir., trabecule; inf., iufuudibulum ; ped., pedicle; V., tri- 

 geminal nerve. Muco-cartilage, red ; soft cartilage, blue ; bard cartilage, purple. 



bars from the sub-chordal cartilaginous rod on each side of the noto- 

 chord, we obtain a picture, as in Fig. 116, in which each branchial 

 segment is defined by the section of the branchial cartilaginous bar 



