448 H. H. NEWMAN 



other group of animals known to the writer, although a much 

 larger number of investigators have chosen to work with echino- 

 derms. Teleosts possess decided advantages over the echino- 

 derms in that they intercross in practically any combination and 

 without the aid of the reagents used in artificial parthenogenesis, 

 which are necessary in order to cross echinoderms, and which 

 may affect the character of development and thus interfere with 

 the study of heredity. It is, moreover, a simple matter to rear 

 the young of teleosts to a stage in which many definitive charac- 

 ters can be studied, while hybrid echinoderms have never to my 

 knowledge been reared beyond a comparatively early larval 

 stage. In addition to these two fundamental advantages tele- 

 osts afford especially good material for this type of investigation 

 because the large number of species in any neighborhood give 

 a very wide range of possible combinations; because the eggs 

 and young are large and easily handled; and because the con- 

 trasting characters are more numerous and more clearly defined 

 than are those of echinoderms. 



HISTORICAL REVIEW OF THE WORK OF APPELLOF, MOENKHAUS, 

 KAMMERER, BANCROFT AND NEWMAN ON TELEOST HYBRIDS 



The earliest published work on teleost hybrids that has come 

 to my attention is an important paper by Appellof that appeared 

 early in 1894. I regret that this paper escaped my notice until 

 after the publication of my two former papers on Fundulus 

 hybrids, for it would have been highly suggestive for certain 

 phases of my own work. The paper, although rather generally 

 overlooked by investigators, should be of considerable interest 

 to all those who are engaged in the study of the developmental 

 mechanics of heterogenic hybrids. Appellof was probably the 

 first to attempt crosses between very distantly related species. 

 His combinations include such ill-assorted matings as the stickle- 

 back and the flounder, the cod and the cunner, the cod and the 

 flounder and others equally bizarre. In each case he found that, 

 even though a mature hybrid between the two parent types be 

 unthinkable, development in the cross fertilized eggs proceeds 



