EXPERIMENTAL STUDIES OX THE ORIGIX OF 

 MOXSTERSi 



I. AX ETIOLOGY AND AN ANALYSIS OF THE MORPHOGENESIS OF 



MONSTERS- 



E. I. WERBER 



Osborn Zooloc/ical Lnhoralory. Yale Universitij 

 {From the Zoological Laboratories of Princeton and Yale Universities) 



EIGHTY-XIXE FIGURES 



CONTEXTS 



I. Introduction 486 



II. The recorded terata 487 



1. Terata of the head 489 



a. The ophthalmic terata 489 



b. Defects of the mouth 492 



c. Defects of the olfactory pits 495 



d. Defects of the ear vesicles 497 



2. The amorphous embryos 498 



in. The microscopic anatomy of the monsters and conclusions regarding 



their morphogenesis 500 



A. Classification of ophthalmic terata 500 



B. The morphology of teratophthalmia 502 



a. Synophthalmia bilentica 503 



b. Sj^nophthahnia unilentica 503 



c. Cj'clopia synophthalmia 507 



d. Cyclopia perfecta 510 



e. Monophthalmia asymmetrica 513 



f. Microphthalmia and anophthalmia 519 



C. The morphogenetic factors underlying the eye terata 521 



1. Stockard's inhibition theory 521 



2. The defect theory of teratophthalmia 528 



' Aided l)y a grant from the Bache Fund of the National Academy of Sciences. 



- Brief reports of the results of this work have been presented and demonstra- 

 tions of material made at the meeting of the American Society of Zoologists in 

 Philadelphia (December 29 and 30, 1914) and at the meeting of the American 

 Association of Anatomists at New Haven (December 28-30, 1915). A preliminary 

 communication was also published in the Anatomical Record (cf. Werber '15 c.) 



485 



