ORIGIN OF MONSTERS 497 



ing of both pits can be found in \'arious synophthalmic and 

 Cyclopean embryos. This observation was made also by Stock- 

 ard on his 'magnesium-embry^os/ but he has not drawn the con- 

 clusion to which the data would seem to point. In a subsequent 

 section of this paper deahng with the microscopic anatomy of 

 some terata the attempt is made to account for the teratoph- 

 thalmic condition, the anomaUes of the mouth and olfactory 

 organs on the basis of a morphogenetic factor common to all 

 of these as well as to other deformities in the head region. 



d. Defects of the ear vesicles. The deformities to which this 

 organ is subject under the influence of the toxic solutions em- 

 ployed in my experiments, vary considerably. Already on ex- 

 amination in toto of most teratophthalmic or otherwise deformed 

 embryos it can be seen (figs. 2, 6, 8, 22) that the ear vesicles are 

 greatly distended and sometimes reach enormous size. In some 

 embryos there may occur a fusion of both ear vesicles, a condi- 



Fig. 30 Amorphous, anophthalmic embryo, with two isohited tissue frag- 

 ments, t.fi. and t.fi., on yolk-sac; from acetone solution (35 cc. gram molec. to 50 

 cc. sea-water), thirteen clays old, p.c, pericardial vesicle. 



Fig. 31 Amorphous, anophthalmic embryo from acetone scdution (^40 cc. 

 gram molec. to 50 cc. sea-water), fourteen daj's old. 



Fig. 32 Dwarfed, malformed embryo with one lateral rudimentary eye, from 

 i\ gram molec. butyric acid, eighteen days old. 



Fig. 33 Amorphous embryo, from acetone solution (40 cc. gram molec. to 50 

 cc. sea-water), fifteen days old. 



Fig. 34 Amorphous embryo from acetone solution (40 cc. gram molec. to 50 

 cc. sea-water), fourteen days old. 



Fig. 35 Meroplastic embryo with rudimentary eyes, from acetone solution 

 (35 cc. gram molec. to 50 cc. sea-water), eighteen days old. 



Fig. 36 IMeroplastic embryo with one rudimentary lateral eye and oedematous 

 ear-vesicles, e.v., from yV gram molec. butyric acid, eighteen daj^s old. 



Fig. 37 Head-meroplast with rudimentary eye; four small tissue fragments, 

 t.f., on yolk, from acetone solution (40 cc. gram molec. to 50 cc. sea-water) four- 

 teen days old. 



Fig. 38 F]gg Avith oedematous eye-teratoma ('solitary eye'), of., oedema of 

 the brain fragment; from acetone solution (35 cc. gram molec. to 50 cc. sea- 

 water), thirteen days old. 



Fig. 39 Egg with eye-teratoma (solitary synophthalmia), .s-c., from acotone 

 solution (40 cc. gram molec. to 50 cc. sea-water), thirteen days old. 



Fig. 40 Egg with 'solitary eye' s.e., and three blastolytic tissue fragments 

 t.f., from acetone solution (35 cc. gram molec. to 50 cc. sea-water), twelve days 

 old. 



Fig. 41 Egg with eye-teratoma ('solitary eye'), from acetone solution (35 cc. 

 gram molec. to 50 cc. sea-water) twelve days old. 



