251 



cross striated (R. lateralis, x.). Tlie line of 

 dashes represents the suppressed portion of 

 the left supraorbital canal. 



Fig. 30. Dorsal view of the brain of a Plaice having an 

 extreme length of 58cni. x 3. The pallium 

 and the choroid roof of the fourth ventricle 

 have been removed, but the asymmetrical 

 position of the pineal tube and body is indi- 

 cated. The dotted line shows the departure 

 from the symmetry. The numbers are those 

 of the cranial nerves. 



Fig. 31. Lateral view of the same brain with the pallium 

 in situ. X 3. lumbers as in preceding figure. 



Plate XI. 



Fig. 32. Embryo Plaice on the 5tli day after fertilization 

 and before invagination of the optic vesicles. 

 x29. 



Fig. 33. Embryo Plaice on the 9th day after fertiliza- 

 tion. The black spots on the body and tail 

 represent the yellow branching chromato- 

 phores which appear about this time. x 29. 



Fig. 34. Embryo Plaice on the iTth day after fertiliza- 

 tion. The embryo is ready to hatch. The 

 branching black markings oai the body and 

 tail are the black chromatophores. The 

 yellow pigment is represented by the grey 

 spots. X 29. Xat. size of this and the 

 preceding eggs --= 1"88 mm. 



Fig. 35. Xewly hatched Plaice, 17 days after fertiliza- 

 tion. The black pigment is represented by 

 the stellar markings, the yellow by the grey 

 spots. X IT. Nat. length = 6'3 mm. 

 Figs. 32 — 35 are drawn from the living og^^ 



