No. 2. — On the Egg Membranes and Micropyle of some Osseous 

 Fishes. By Carl H. Eigenmann. 1 



At the suggestion of Dr. E. L. Mark, I undertook the study of the 

 development of the micropyle and egg membranes in some of the bony 

 fishes. 



The eggs of the following species were examined : Amiurus catus, 

 Tachisurus sp. (T), Catostomus teres, Notemigonus chrysoleucus, Caras- 

 sius auratus, Clupea vernalis, Alosa sapidissima, Fundulus heteroclitus, 

 F. diaphanus, Apeltes quadracus, Pygosteus pungitius, Lepomis mega- 

 lotis, Morone americana, Esox reticulatus, Anguilla anguilla rostrata, 

 Cyclogaster 2 lineatus, Gadus morrhua, and Hippoglossoides platessoides. 

 In many of these species the eggs were not in a condition favorable 

 for tracing the development of the micropyle or even the membranes. 

 My account will be confined to the eggs of Amiurus catus, Notemi- 

 gonus chrysoleucus, Clupea vernalis, Fundulus heteroclitus, Pygosteus 

 pungitius, Perca americana, Morone americana, Esox reticulatus, and 

 Cyclogaster lineatus. 



I am indebted to Dr. Mark for the use of his manuscript abstracts 

 of the papers on egg membranes published before 1881. 



It has long been known that fish ova are provided with a membrane, 

 the zona radiata. The eggs of certain fishes have, in addition to and 

 outside of the zona radiata, a second membrane which bears in some 

 cases long filaments, in others short processes which serve to attach the 

 eggs to foreign bodies. 



Fundulus heteroclitus and F. diaphanus. 



The fact that the eggs of some fishes are provided with long filaments 

 was first noted by Haeckel ('55 ). He found them on the eggs of many 

 species of Scomberesocidae, but mistook their position, describing them 

 as thin fibres lying inside the egg membrane (zona radiata). A con- 

 nection of the fibres with cells could not be traced. 



1 Contributions from the Zoological Laboratory of the Museum of Comparative 

 Zoology at Harvard College, under the Direction of E. L. Mark. — No. XVI. 



2 Liparis of authors. 



vol. xix. — no. 2. 9 



