ORIGIN OP MONSTERS 489 



ot them. In a pre^'ious publication (Werber '15 c), I have pre- 

 sented a brief survey of the I'ecorded terata. While a more 

 complete presentation of them is attempted in this paper, I am 

 fully convinced that it is inadeciiiate to convey the proper im- 

 pression of the great range of A'ariation in the noted effects. 



1. Terata of the head 



The malformations of this part of the body are many and 

 unusuall)" \'aried. Indeed, as will be pointed out later, this 

 part of the body appears to be the most susceptible one to the 

 influence of toxic solutions. The deformities of the head affect 

 the sense organs, the brain, the mouth, and the skull. All of 

 them are usually found to occur in various combinations. The 

 most striking ones on examination in toto are those that concern 

 the eyes. 



a. The ophthalmic terata. When Fundulus eggs are subjected 

 to the action of butyric acid or acetone in the concentrations 

 stated above, embryos with normal eyes are of the rarest occur- 

 rence. Cyclopia, i.e. the presence of a single median eye is 

 found very often. I have likewise recorded in my observations 

 a wide range of intermediate stages between two normal eyes 

 in the typical position in the head all the way down through 

 more or less closely approximated eyes or eyes of an apparent 

 double composition and true cyclopia to complete anophthalmia 

 as described so often by the older teratologists and as obtained 

 experimentally in recent years by Spemann ('04), Lewis ('09), 

 Stockard ('09, '10 b), and others. 



A comparison of figures with the normal embiyo in figure 1 

 is very instructi\'e of this gradual transition from the normal 

 eyes to various synophthalmic or cyclopean defects. In figure 

 2 an embryo is seen witli eyes apparently normal, but for their 

 position. They are located on the frontal part of the head in 

 approximation to one another and, while not being fused exter- 

 nally, they are found to be so on examination of sections at a 

 more posterior level. A more intimate approximation of the 

 eyes is to be seen in figure 3. Here the eyes already are con- 



