191 



the brain to the category of "amacrine cells", that is cells which are 

 not provided with axones. On p. 661 the author says : "Die Menge der 

 amakrinen Zellen ist bei Ammocoetes nicht dermaßen in Gruppen ge- 

 teilt, daß die Kerne unterschieden werden können, welche Johnston 

 in diesem Gebiet beschrieben hat." We must suppose that there is a 



X vs 

 Fig.4&5 



iasc. com. 



Fig.ö 



Fig. 8. A diagram of the visceral and somatic sensory columns in the hindbrain 

 of Lampetra as seen from the dorsal surface, and the nerve roots related to each column. 

 som.sens. somatic sensory column, vise. sens, visceral sensory column, the reference 

 line resting on the nucleus commissuralis. The cranial nerves are numbered by the 

 usual Roman numerals and to these are added letters to indicate the functional com- 

 ponents represented, ss. somatic sensory (cutaneous), v. s. visceral sensory (general and 

 gustatory). LI. lateral line fibers. The location of Figs. 1 — 7 is shown approximately. 



difference here between the species studied. I have not studied the 

 ammocoetes of Lampetra, but in the ammocoetes of P. dorsatus the same 

 arrangement of the sensory nuclei is to be seen as in the adult Lam- 



