GREGORY: FISH SKULLS 



209 



no orbitosphenoid and the basisphenoid is absent or reduced to a mere vestigeal ossification. 

 In all these respects the Osmosudidae [Figs. 88, 89] show a perfect continuation of the series 

 already started by the subgenus Bathysudis (gen. Lestidium, see Parr, 1928, d. 42). . . . 



■me/h 



pmx. 



epio/ 



smy. 



Lestidium speciosum 



Fig. 88. Lestidium speciosum. After Parr. 



"The evolution of the phylogenetic branch represented by the Scopelarchidas, Ever- 

 mannellidje, and probably also by the Cetomimidae has followed along lines entirely opposite 

 to those of the just considered forms derived from a Chlorophthalmus-llke ancestral type. 



Omosudis lowei 



Fig. 89. Omosudis lowei. After Parr. 



