neal: nervous system in squalus acanthias. 



151 



Table I. — EXCEPHALTC SEGMENTS. 



'55 

 '77 

 '85 

 '87 

 '89 

 '90 

 '91 



'84 

 '87 

 '85, '89 

 '85, '89 

 '90 

 '91 

 '92 



'75 

 •86, '93 



'90 



'91 

 '92, '92» 

 '92, '92» 



'92 



'75 

 '84, '85 

 '87 

 '89 

 '91 

 '91 

 '93 

 '94 

 '94 

 '95 



Remak . . 



Mihalkovics 



Rabl . . . 



Be'raneck 



Piatt . . . 



McClure 



Zimmermann 



Be'raneck 

 Orr . . 

 Hoffmann 

 Hoffmann 

 McClure . 

 Clarke . 

 Herrick . 



Goette . 

 Kupffer . 

 McClure . 

 Waters . 

 Froriep . 

 Froriep . 

 Wiedersheira 



Dohrn 

 Kupffer . 

 Scott . . 

 Piatt . . 

 Waters . 

 Zimmermann 

 Kupffer . 

 Kupffer . 

 Locy . . 

 Locy . . 



Dog. . 

 Ox . . 

 Kabbit 

 Sheep, Mouse; 

 Swine . , 

 Rabbit 

 Mole . 

 Man . . 



Chick 



Lizard 



Man 



Tropidonotus 

 Lizard . 

 Alligator 

 Snake . 



Bombinator 

 Salamandra 

 Amblystoma 



Salamandra 

 Triton . .' 

 Salamandrina 



Teleostei . 



Petromyzon 

 Salmon 

 Cod . . . 

 Acanthias . 

 Acipenser . 

 Ammoccetes 

 Squalus 



F.B. 



3? 



H.B. 



G 

 6 

 5-6 

 5 

 5 



5-6 



^6 



6-7 



6 



6 



5 

 6 

 7 

 7 

 6 

 5 

 5-7 



8-9 

 5 

 5 

 5 

 6 



6 



6(8) 



Total. 



13 

 12 



10 

 13 



10 



9 



10 



4 



5 



11 

 13 

 13 



11 

 14-16 



investigators upon neuromerism have been seldom, if ever, so far ex- 

 tended as to determine the number of segments finally included in the 

 head. The reason for this has been that the hindbrain neuromeres dis- 

 appear before their relations to the posterior limit of the cranium can be 

 determined. Table II. gives the nerve relations in different Vertebrates, 



