24 MALL. [VoL. XIX. 
pathological changes ii them are so radical that their lives 
are also short. Amorphous forms are analogous with lithium 
larve and identical with the nodular form in man. In gen- 
eral, only part of the embryo continues to develop in an 
irregular fashion and finally the whole embryo dies. The 
flattened forms, with and without blood-vessels, are identical 
in man with the vesicular forms, that is, ova containing 
umbilical vesicles only, and to ova without embryos, respec- 
tively. 
The merosomatous monsters in which the whole embryo 
is affected, total monsters as they are also called, are not 
likely to live long, but they are of great interest to those 
studying teratological problems. While they are being formed 
a certain number of eggs develop into partial monsters, and 
in man some of them grow into foetuses which may go on to 
full term, and a very small number of them live on to maturity 
after birth. 
The recent total monsters produced by Bardeen’ in sub- 
jecting the sperm of toads to X-rays before fertilization can 
be explained on the same ground as are lithium embryos. The 
tadpoles which develop from such eggs are entirely diseased, 
continue to grow in an irregular manner and appear much like 
lithium larve in Fundulus or as ordinary pathological embryos 
in man. In all three cases the primary radical change involves 
the whole embryo; in Bardeen’s experiment the cause af- 
fected the sperm before fertilization, in Fundulus shortly 
after fertilization, and in human pathological embryos some- 
what later. Although the methods employed are very differ- 
ent, the principle involved and the results obtained are much 
the same. 
A very large number of monsters are to be classed as total 
monsters. They are probably brought into existence by a 
variety of circumstances, all of which interfere with the 
nutrition and growth of the whole embryo and the changes 
in them are so radical that their lives are very short. In man 
"Bardeen, Jour. Ex. Zool., IV, 1907. 
