24 PROCEEDINGS OP THE AMERICAN ACADEMY 



years, some of tliem belonging to the Flounder, to Ctenolabrus, to 

 CoLtus, to Lophius, and to 'I'autoga. 



According to Emery,® the eggs of Fierasfer are also pelagic. 

 Kiugsley and Conn ^ have also studied the pelagic eggs of Ctenola- 

 brus ; they state that Mr. Van Vlcck has observed those of Merlucius, 

 and also figured an egg with an oil globule ; and finally Ilensen ^'^ has 

 published a most interesting paper on the occurrence of the eggs of 

 a few of the fishes of the Baltic at the surface. 



During the season of 1883 a good deal of the dilhculty, and conse- 

 quent confusion, existing in distinguishing the many species of pelagic 

 eggs met with during the summer at Newport, has been overcome, 

 and we are now able to distinguish no less than twenty-two species of 

 pelagic eggs, nearly all of which have been referred to some of the 

 many young stages of osseous fishes which have been collected at the 

 surface for a series of years. 



The differences between these pelagic eggs are very slight, and the 

 greatest possible care is necessary not to confuse eggs of very dis- 

 similar fishes. I may give as an instance that the eggs of Ps. melano- 

 gaster and of an undetermined Flounder had, till this year, been 

 confounded with those of Ctenolabrus ; those of the Brown Flounder 

 with those of two species of osseous fishes as yet undetermined ; 

 those of a species of midetermined Flounder with those of Heniitrip- 

 terus ; and those of the Sienna Flounder with those of the Yellow 

 Flounder. As these different pelagic eggs must go through extensive 

 changes in the course of their development, changes in the appearance 

 and growth of pigment spots of the body and of the yolk, it is almost 

 impracticable, without any extensive series of sketches, to establish 

 with certainty the identity or difference of closely allied eggs. Hen- 

 sen has called attention to the ellipsoidal shape of some of the pelagic 

 fish eggs ; this is particularly striking in the egg of an Osmerus (?) ; 

 in this the difference between the longer and the shorter axis can be 

 detected by the eye. Tlie yolk mass of this egg is remarkable for 

 being segmented in large polygonal cells ; a similar, but incomplete 

 sesmentation occurs in the eggs of the Brown Flounder. 



The pigment spots of the surface of the yolk, and those character- 

 istic of different species of fish embryos, begin to make their appear- 



8 Emery, C. Fierasfer. Arbeit aus d. Zool. Station, zu Neapcl. 



9 Kingsiey, J. S., and II. W. Conn. Mem. Boston Soc. Nat. Hist., III., 

 No. VI., 1883. 



10 Ilonsen, V. Bericht der Com. zur Wiss. Untersuchung der dcutsclion 

 Mecre, IV. Iviel, 1883. 



