VTRAL NERVOUS SYSTEM IN PIANARIA. 



47 



IV. TERATOMORPHIC HEADS. 



i 1 lu- first case to be described is shown in Fig. 10. Here the 

 auricles appear on the front of the head and extend anteriorly. 

 The anterior margin of the head between them is slightly rounded 

 instead <>t pointed as in the normal animal. In tin- median line 

 is a -in.'li- eye. 



- tions of the head region of this animal are shown in Figs. 

 11-15 The eye is situated almost at the extreme .interior end 



to 



FIGS. 10-15. 



"I i IK- \ .ionic mass and a few sect inn- anterior io it tin- 

 in-! -\nu- -\-tc-ni appears as in Fig. 11. Mere four filter tracts 

 Mirnumded by cells are visible and are e\identl\ nerves t the 

 anterior re-ion- of the head. The conditions ai the le\ el <>!' 

 the eye are -lnwn in Fig. 12. The -inije optic pigment cup 

 open- anteriorly instead of laterally, as the adjoining -ectinn- 

 on the -lide -ln>\\ . and it is farther from the dor-al -urla< e ot' tin- 

 head and more nearly imbedded in the u.uu-!ionie ma than in 



