THE CENTRAL NERVOUS SYSTEM IN TERATOPH- 

 I' HALM 1C AND TERAT()M< >KPHIC FORMS OF 

 PLANARIA DOROTOCEPHALA. 



C. M. CHILD AND E. \'. M. McKIE. 



The -tudv of the nervous system in tin- teratoplnhalmic and 

 teratomorphic forms of Planaria dorotocephahi \\a- undertaken 

 by i In- junior author of this paper at the senior author'- sugges- 

 tion. 1 h<- results of this study were accepted as a the-i- for the 

 M.i-i. ree by the Department of Zoology of tin- l'ni\i T-itv 



o! ( hi. .1-0. Since the results of the work an- of ( -on-iderablc 

 inten-t .m<l since- Miss Mi-Kit- was prevented by \.iriou- cir- 

 ciim-i.iiice- from preparing the paper for publication, the -enior 

 author ha- undertaken, at her express request, to revise her manu- 

 3< ript lor publication and to add some figures from her -lide-; he 

 h.i- also added a section on the various method- b\ \\hich the 

 teratophthalmic and teratomorphic forms have been produced 



and ha- e\ii-udrd sollU'what the scope ot the di-cn--ion ot the 



results. 



The primary object of the work was to determine the general 

 form and tin- degree of development of the cephalic part of the 

 central IK i \ oiis system in these abnormal form- as compared 

 uith normal animals. The observation- concern chiellv the 

 teraiomorphii form* since these repre-eiit a more extreme 

 departure I'mm the normal type and afford more definite and 

 -tiikin^ re-nit-. 



The animal- for sectioning were anesthetized with \\eak alcohol 

 beloif iixation iii hot (Wilson's fluid or -nblimate. Sections were 

 cm ten micra in thickness. Frontal ami -au'ttal as well as trans- 

 verse sections \\i-re made, but all the h-uiv- are drawn from trans- 

 \ ei se sections -incc these show the e--ential feat ure- most clearK'. 



Ml li-uie- of sections were drawn to the same -calc with 

 the camera. They are designed to -ho\\ . tir-t tin- -eiieral form 

 of the nerxou-, -\-tem and second, the general relation^ bet \\een 

 filler tracts and cell>. The cell- are repre-ented merel>- by small 



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