NEAL! NERVOUS SYSTEM IN SQUALUS ACANTHIAS. 151 
TABLE I. — ENCEPHALIC SEGMENTS. 
F.B. | M.B H.B Total. 
142 | Bischoff. . . Dog. ee 6 
i WO- Ray: aa 0% P 82 6 
= ’77 | Mihalkovics . Rabbit A 5-6 
a ’86 | Kupffer. . . Sheep, — Man 5 
E "89 | Prenant. v . Swine . 5 
= 791 | Zimmermann . Rabbit et 2 3 8 13 
e 192, 922 | Froriep . . . Mole 2 8 7 12 
2905 | Broman . . . Man. 7 
AT IA a ARPA 5-6 
’77 | Mihalkovics . r Gian eee 5-6 
ES 185 RAL a vs = eerie KR 6-7 
A 287 | Béraneck . . A az 2 1 6 9 
a A ER nase ene. i Pp pp 1 1 6 8 
790 | McClure . . re A 2 2 6 10 
’91 | Zimmermann . = OT 2 3 8 13 
84 | Béraneck . . Lizard . ER 5 
a HAA BL SRN ae ie Ma PIN Ss 9 1 6 9 
A | ’85,’89 | Hoffmann . . gi Í 7 
a | ’85,’89 | Hoffmann . . Tropidonotus 7 
a 90 | McClure. . . Lizard. . aves Me Velie 6 10 
a ‘Ol | Clarke”... Alligator =< rae 5 
ORT TEISTNOR ts cary T SRE a ee 5-7 
¿ "5 |Goette . . . Bombinator . 2 
Z | 86,98] Kupffer... Salamandra... 5 3 2 
= ’90 | McClure. : . Amblystoma hae 2 2 5 9 
la a O aa q g 2 5 10 
m | 92,92% | Froriep . . . Salamandra . . . 4 
| 92,983 |-Eronlep....... Trit ton... rc 5 
<q "92 | Wiedersheim . Sal: amandrina my 1 2 a 2 
TO (WORT  . s a: OÍDOS TOL cni a> 8-9 | 
"34, 80." Rupr y 3 % TORE 3 5 
"87. Bootb.. 4. + Petromyz20n: . 8 5 
a 89 Elo. si MO se es 5 
= 91 Waste eri God's “4 et 8 2 6 11 
a 191 | Zimmermann . Acanthias. . Pa lee 3 8 13 
aa 703 | Kupffer . . . Acipenser, . +. » | 5 3 | 5 13 
’94 | Kupffer . . . Ammoceetes . 8 
OR BOOY San cs QUA: rs 8 2 | 6 
WO | OOM A 3. = ra... 3 2 | 6 (8) | 14-15 
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, 
