352 GUDRUN RUUD 



The lateral line system of Spinax only in a few details differ from this. 



In Spinax the hyoid and mandibular groups of ampullæ are united to 

 one hyomandibular group on each side and the inner and outer buccal 

 groups to one great median buccal group. Further the mandibular canal 

 is absent in Spinax; there is no communication between the dorsal and 

 ventral parts of the supra-orbilal canal, and nothing of the canal between 

 the temporal commissure and the supra-orbital is innervated by the late- 

 ralis nerve. At last the pit organs are arranged in a way. that agrees 

 more with that of Mustellus laevis and even Amia calva as described by 

 Allis (2 and 1). 



Trykt 29. april 1915. 



