428 'Journal of Comparative Neurology and Psychology. 



Fig. 7. Section through the brain of Conger .22 mm. farther caudad, showing the visceral com- 

 missura infima and nucleus, and the somatic commissura infima passing between the somatic sensory 

 fields. The latter area at this level may be regarded as lateral funicular nucleus. Internal arcuate 

 fibers pass from it to the ventral commissure. 



Fig. 8. Section through the brain of Conger .4 mm. farther caudad at the level of the first dorsal 

 root of the first spinal nerve. At this level the visceral commissural nucleus is less sharply separated 

 from the adjacent somatic centers. A root passes from the nucleus ambiguus out into the first dorsal 

 spinal root {rx. XI?). Its peripheral course is unknown. The somatic sensory field is desginated nuc. 

 funiculi lateralis, and the cephalic end of the median funicular nucleus appears ventrally of the spinal 

 V tract. This nucleus receives termini of the spinal V tract and of the first spinal nerve and is related 

 with the fasciculus dorso-lateralis. Internal arcuate fibers from both the lateral and the median funicu- 

 lar nuclei cross in the ventral commissure and largely enter the ventral funiculi within which they turn 

 caudad for the most part. 



Fig. 9. Section of the brain of Conger .3 mm. farther caudad, through the somatic commissural 

 nucleus. The visceral commissura infima and its nucleus have disappeared, vestiges only being appar- 

 ent dorsally of the somatic commissural nucleus. The portion of the somatic commissura infima which 

 crosses between the somatic sensory fields dorsally of the visceral nucleus (Figs. 6, 7, 8) has also dis- 

 appeared, but tracts passing forward into that commissure from the lateral funicular nucleus are seen at 

 ^j. A broad diffuse somatic commissura infima appears ventrally of the visceral nucleus associated with 

 the somatic commissural nucleus. The latter is also closely associated with the formatio reticularis 

 and median funicular nucleus. 



