TELEOST OVUM. 55 



present time it is, obviously, impossible to account for the occur- 

 rence of these remarkable cases. However, it is hoped that an 

 anatomical investigation of early stages in the development 

 of eggs subjected to the influence of the environmental modi- 

 fications used in these experiments, may give at least a clue as to 

 what may have happened in the development of these eggs. 

 Practically all other known deformities of the eye such as total 

 blindness, or presence of lenses only, or presence of supernumerary 

 lenses were frequently found. 



To the student of the physiology of development the occurrence 

 in these experiments of large numbers of anterior hemiembryos 

 which seem to be closely analogous to those obtained by mechan- 

 ical means by Roux,^ Endres,^ Morgan^ and K. Ziegler'* will be 

 of special interest. As will be pointed out soon the formation 

 of the hemiembryos in these experiments may also possibly be 

 due to similar factors. 



A great number of embryos were hydrocephalic and so far as 

 could be determined it is reasonable to expect that an anatomical 

 investigation may reveal in some deformed embryos oedematous 

 conditions, also herniae and other mechanical obstructions which 

 played a part in their formation. 



Striking abnormalities of the heart and blood-vascular system 

 were found in all malformed embryos with the exception of those 

 which showed only median cyclopia. Some were entirely devoid 

 of the heart, while other possessed an exceedingly delicate tube 

 in its place which was practically straight and of about the size 

 of the intestinal blood vessels in a normal embryo of a corre- 

 sponding stage. The rate of the heart beat varies with the 

 degree of the abnormality of the organ, and is, as a rule, very slow 

 in all monstrous embryos. The range of variation in the develop- 

 ment of the blood vessels is very wide. There may be merely 

 blood islands scattered on the yolk-sac, rudimentary, imperfectly 

 connected, or in some instances more or less normal vessels. 



1 Roux, W., "Gesammelte Abhandlungen zur Entwicklungsmechanik der Or- 

 ganismen," II., 1895. 



2 Endres, H., "Anstichversuche an Froscheiern," Sitzher. d. zool.-bot. Sektion 

 d. schlesischen Ges. f. vaterlandische Kultur, 1894. 



' Morgan, T. H., "The Formation of the Embryo of the Frog," Anat. Anz., 1894. 

 ^ Ziegler, K., "Zur Postgenerationsfrage," Analomische Hefte, Vol. LXVI., 1902. 



