EXPLANATION OF THE PLATES. 55 



Near the 1 imc of batching. 



Young Flounder, twelve tours old, seen from ventral side. 



A profile view of a specimen, about thirty hours old, showing a variation from the more typical 



pigment-marking seen in the following figure 

 Of the same age .-is Fig. 6, but with a more characteristic arrangement of pigment spots 

 About sixtj hours old. Yolk-sac lias uearh; disappeared. Four well-marked pigment-patches. 



Eye green «i ith coppery reflection. 

 About eighty-four hours old. Pigment nearly the same as in Figs, 8 and 10. The granular 



surface is here more l'nlU represented thau in the oilier figures. 

 Eighty-four hours old. 



PLATE XVII. 



Species No. 10. 



Figs. 1-3. 



Fig. 1. Shows the character and distribution of the pigment in the emhryo shortly before batching. Sup- 

 posed to belong to the same species as Figs, - and ;>. x 55. 

 Fig -2. Represents a young fish uol less than three or four days old. 



Fig. 3. A later stage, in which the vent, lias taken a marginal position, and the black elnomatojihorcs have 

 become very large and conspicuous. 



Osnierus moidax, (Jill. 



Figs. 1-6. 



Fig. 4. Supposed to be the egg of Osmerus manias, Gill. The entire yolk is segmented. The embryo is 



long and slender, and shows no trace of pigment. 

 Fig. 5. Just hatched, measuring 5 mm. in length, seen from above. 

 Fig. 6. Same, seen in prolile. 



PLATE XVIII. 



Motella argentea, Rutin. 



Figs. 1-G. 



Fig. 1. An egg at the time when the blastopore is nearly closed. The chromatoblasts arc beginning to 

 appear, but as yet there is no trace of pigment. X 55. 

 The same, six hours later. Granules of black pigment, appear in the chromatoblasts. X 55. 

 The same, twenty-four hours later. Dendritic chromatophores more numerous on the body than 



on the yolk. X 55. 

 The same, twenty-four hours later. X 55. 



Just before batching (twenty-four hours later than Fig. 1). Arrangement, of pigment now anticipates 

 the more advanced stage of concentration in definite regions, seen in Fig. 6. X 55. 

 Fig. 6. Twelve hours after hatching. Eye is black. 



Species No. 23. 



Figs. 7-10. 



Fig. 7. Represents the earliest stage obtained. Four pairs of yellow pigment-clusters characterize this 



egg. X 55. 

 Fig. S. At the time of hatching. X 55. 

 fig. 9. Thirty-six hours old. Pigment in a state of expansion. 

 Fig. 10. Three days old. Yellow pigment much reduced. 



