PLATE 43. 



CESTRACIONTIDAE, CARCHARINIDAE, and SQUALIDAE. 



Fig. 1. Cestracion TiBURO (Page 160). Fig. 2-3. Cestracion zygaena (Page 157). Fig. 4- 

 Carcharinus platyodon (Page 126). Fig. 6-8. Galeocerdo arcticus (Page 148). Fig. 9-1 

 Squalus acanthias (Page 192). 



From the brain of the Carcharidae, Plates 40 and 41, there was in the Vulpeculidae, Plate 4S| 

 marked increase in the plication of the hind brain with a less considerable one in the size of the fore brsl 

 In Plate 43, the much greater advance of the Cestraciontidae is seen both in the volume of the fore br j 

 and the complexity of the hind brain; these are more advanced in the Cestraciontidae than in 

 Carcharinidae, the nearest allies, for instances see fig. 4, Carcharinus platyodon, and figs. 6-8, Galeoce\ 

 arclicus. That the archaic family Squalidae is much lower in rank is indicated by the smooth hj 

 brain and the smaller amount of the fore brain. 



