58 C. M. CHILD AND K. V. M. McKIE. 



nerve cords arise near the level of the auricles. In the teratoph- 

 thalmic forms with partially fused eyes the eyes lie nearer 

 the anterior end of the gangliei and the right and left portions 

 are not separated at the level of the auricles. The eyes of the 

 teratomorphic forms are situated at the extreme anterior end 

 of the ganglionic mass. 



4. The abnormal structure of the nervous system in the 

 teratophthalmic and teratomorphic forms continues posteriorly 

 through the regenerated anterior end to the- level of the old 

 tissue and even the nerve cords in the old tissue may he more or 

 U>s different from the normal. In some teratomorphic forms 

 the regenerated nervous tissue apparently begins to break up 

 into separate nerves a short distance posterior to the eyes, but 

 resumes the form of two nerve cords in the old tissue. 



5. In the normal animal the optic pigment cups open laterally 

 and the same is true for the teratophthalmic forms with partially 

 fused eyes. In the teratomorphic forms the cup opens anteri- 

 orly or antero-ventrally and in some cases more or less to one 

 side. The single median eye may be connected by two nerves 

 with right or left portions of the ganglionic mass, or by a single 

 nerve with either one, or the optic nerve may arise from the 

 median region of the ganglion. The eyes are also farther from 

 the dorsal surface in the teratomorphic than in the normal forms 

 and are sometimes more or less completely imbedded in the 



ganglionic mass. 



HULL ZOOLOGICAL LABORATORY. 

 UNIVERSITY OF CHICAGO, 

 October, 191 1. 



REFERENCES. 

 Child, C. M. 



'na Studies on the Dynamics of Morphogenesis and Inheritance in Experi- 

 mental Reproduction. I. The Axial Gradient in Planaria dorotocephala 

 as a Limiting Factor in Regulation. Journ. Exp. Zool., Vol. X., No. 3, 

 191 i. 



'nb A Study of Senescence and Rejuvenescence Based on Experiments with 

 Planaria dorotocephala. Arch. f. Entwickelungsmech., Bd. XXXI.. II 

 A, ion. 



'lie Experimental Control of Morphogenesis in the Regulation of Planaria. 

 Biol. Bull., Vol. XX., No. 6, 1911. 



"nd Studies on the Dynamics, etc. II. Physiological Dominance of Anti-iini 

 over Posterior Regions in the Regulation of Planaria dorotocephala. Journ. 

 Exp. Zool., Vol. XL. No. 3, 1911. 



