110 



MR. E. S. GOOBRICH ON THE OCCIPITAL REGION 



arch has not appeared, the ventral portion of the first myotome is 

 larger, a ventral nerve-root is seen supplying myotome 2, and the 

 neural arches are mostly in a procartilaginoas state. 



Text-fig. 40 is a partial reconstruction of another larva of about 

 the same stage, but rather younger. The ventral portions of 

 myotomes 1 to 6 are shown, also the spinal ganglia. Procartilage 

 vaguely indicates the position of the aiiditory capsule, the occipital 

 arch is scarcely yet marked out, but the next three neural arches 



Text-jBg. 41. 



Text-fig. 42. 



Reconstructions of the anterior region, seen from tlie right side. The visceral arches 

 and auditory sac are seen in text-fig. 4il ; these have been removed in text- 

 fig. 42, where the nerves are shown. 



have begun to develop ca,rtilage. The first myotome is quite, 

 and the second myotome nearly, cut into a dorsal and a ventral 

 portion by the roots of the glossopharyngeal and vagus. The 

 ventral remnant of the first myotome (2nd somite) varies con- 

 siderably in development, for in the younger larva drawn in 

 text-figs. 41 and 42 it is hardly distinguishable. At this stage the 

 trabeculse and visceral arches are the only skeletal elements visible, 

 and true cartilage can scarcely be said to have appeared. 



