CENTRAL NERVOUS SYSTEM IN PLANARIA. V^ 



In Case I where the auricles are a considerable distance apart 

 (Fig. 10) the fusion of the ganglia (Figs. 11-15) * s more complete 

 and their structure is more abnormal than in Cases 2 (Figs. 16- 

 18) and 3 I L-. 19-22), where the auricles are nearer together. 

 In Cases 4 .ni'l 5. where Uvo eyes develop close together, far 

 from the -urface and in abnormal relations to each other and 

 where the auricle- are partially fused, the ganglionic region is 

 highly abnormal. 



\\lien. ho\\e\er, we compare the teratophthalmic with the 



lomorphic forms it is evident that a general parallelism be- 



tueei! tin- external features of the head and the condition of the 



nervous system does exist. So far as the observation- go at 



in. tin- 111 r\ oiis system is always more abnormal in the 



irraioini.rphii !<>rms than in the teratophthalmic form- \\ith 



partialK tu-ed t 



\ n gards the eyes themselves certain points are of inttn-t 

 In the normal and partially fused eyes the pigment cups open 

 laterally, \\hile in the teratomorphic forms they open anteriorly 

 or an 1 1 -i < i- \em rally. Moreover, the eyes are usually farther from 

 tin doi-s.il -urlace of the head in the teratomorphic form- than 

 in other-. 



1 In -iiu'le <-ve of the teratomorphic head may be connected 

 \\ith both -ide- of the ganglionic mass (Fig. 18) or with only one 



I i. j i and in case two optic cups arise in the teratomorphic 

 hea-l I =, and 2(>) they may both be connected with the -ame 



part nt t ! . limi. 



The pM-itioiiof the eyes or eye on the ganglion may differ more 

 or less ui'lek in the normal and abnormal forms. In the normal 

 animal Figs, i 5) the eyes lie dorsal to the posterior region of t hi' 

 ^airjioii. \\liii-h divides a -hort distance behind them into the 

 t\\o nerve cords. In the teratophthalmic forms with partialK 

 fn-eil eyes a . cn-iilerable portion of the ganglion lie- anterior 

 to the eyes M^. 7) but the right and left sides of the nervon- 

 system remain united farther posteriorly than in tin- normal 



I k-. 5 and T. In the teratomorphic forms the eye lies dor-al 

 to the extreme anterior portion of the ganglion and the t\\<> eonl- 

 do not become -eparated for a considerable di.-tance posterior 

 to it 



