LETTERING ADOPTED IN ALL THE FIGURES. 



anus. 



air-bladder. 



blastoderm. 



branchial bar. 



blastodermic rim. 



clavicle. 



epiblastic ridge connecting pectoral and pelvic 



fins, 

 cortical vesicles or segments of yolk, 

 site of permanent first dorsal fin. 

 permanent second dorsal fin. 

 precephalic vesicular expansion of dorsal fin. 

 fore-brain. 



filaments of attachment process, 

 gall-bladder, 

 heart. 



hyomandibular cartilage, 

 hypural lobe of tail, 

 hyoid arch. 

 Kupffer's vesicle, 

 liver. 



lateral sense organ, 

 mouth, 

 mid-brain, 

 micropyle (closed), 

 medulla oblongata. 



EXPLANATION OE PLATE L. 



Figs. 34 to 39. 

 [The pigment, except when otherwise specijied, is shown as by reflected light.'] 



Figure. 

 34. 

 35. 

 36. 

 37. 

 38. 

 39. 



Larva of Species I. Solea. (?) Profile view. 



Dorsal view of anterior region of the same. 



Larva of Species VIII., about twelve hours after hatching 



Larva of TracMnus vipera, shortly after hatching. 



The same, early post-larval stage. 



Larva of Pleuronectes microcephalus (by transmitted light). 



[8] 



