530 



H . H. New??iafi 



almost normal. In none of the specimens examined was the circu- 

 lation normal. In some it was partial, while in the majority it 

 was totally lacking, except in the heart itself. Much of the ill 

 success in development was probably attributable to some lesion 

 in the circulation, for which a reason will be suggested in the dis- 

 cussion. 



S 



Figs. 3 to 8 (inclusive) represent types of monstrosities in the H hybrid strain, dissected out of the 

 egg membrane, after all specimens capable of hatching had done so. These are camera lucida draw- 

 ings, showing a magnification of I2 diameters. 



Fig. 3 represents a common type, well advanced, but with some lesion in the circulatory system. 



Fig. 4 represents an unusual type, in which the pectoral fins and the eye have continued to develop 

 independently of the cessation of growth in the rest of the body. 



Figs. 5, 6 and 7 show types of the tailless monster, the most frequent abnormality. 



Fig. 8 represents an uncommon type, a headless monster. The head region is represented by a very 

 small, shrunken, heavily pigmented mass. 



Considerable independence was seen in the development of 

 different regions. Head may develop while trunk is retarded 

 and vice versa. The fins in one case had continued to develop 

 after the rest of the body had ceased to grow. 



A considerable number of H hybrids of this series are at the 

 present time being reared in aquaria at the United States Bureau 

 of Fisheries at Woods Hole, Mass. 



