558 E. I. WERBER 



tation of the double, fused brain. Here an additional assump- 

 tion may be made, namely that fragments of the blastolyzed 

 embryonic primordium have secondarily come to fuse owing to 

 shifting caused by increased osmotic pressure. Such spatial dis- 

 tortions and shif tings can be recognized in many duplicities. 

 In our present case this hap-hazard regulation and fusion of 

 parts would seem to be evidenced by the unusual position of 

 an optic cup on the ventral side of the posterior part of the 

 brain (cf. fig. 86). 



That amorphous monsters result from blastolytic injury of a 

 high degree is well illustrated also by the anophthalmic and 

 greatly malformed embryo in figure 31. 



Besides the defects and malformations which are seen on 

 examination of the embryo in toto more are disclosed when sec- 

 tions are examined. There is no trace of eyes, and the nervous 

 system is lacking almost entirely. In transverse sections (fig. 88) 

 through the region of the head only some muscles, connective 

 tissue, cartilage (of maxillary or mandibular arches?) and very 

 rudimentary, closely approximated ear vesicles can be seen. In 

 a few, more posterior sections there can be seen what might be 

 taken for a very faint suggestion of nervous tissue in a very 

 poorly differentiated stage. It is evidently this exceedingly 

 small remnant (only seven sections of 7/x thickness) of the 

 nervous system that has given rise to sensory part of the ves- 

 tigial ear vesicles. Somewhat further posteriorly transversely 

 sectioned coils of the intestine come into view. No trace can 

 he found of either the notochord or the spinel cord. The fins, 

 which also come into view at this level, are oedematous and 

 filled with plasma (fig. 89). A few sections further posteriorly 

 there is seen ventrally from the intestine a large coelomic cavity 

 containing some fibrin. This cavity enclosed by the body wall 

 is practically all that can be seen in the last sections of the 

 monster. 



IV. CONCLUDING REMARKS 



It has been shown in the foregoing that an almost endless 

 variety of monstrosities can be produced in fish, if eggs in the 

 very earliest stages of development are subjected to the action 



