70 



Gaslecosteuy (see fig. 3), double-sided in a s|)eciirien eacli of' Beioiie 

 and Exoi'oetes). However, I want to consider (his course as aberrating, 

 for in another specinfien of Gasterosieus and also of Exocoetus it 

 runs laterally to the tr. strio-thalamicus, as with the other Teleosts. 



Fibrae tect. "\J 

 n. opt. 



/^'2^-J \i\^m\ '1113 r/f;i>'///r^//'^-., '.^V 



■si 



tecto- 

 praerot. mihi 



praeteit. 



Tr. tecto-praerot. mihi for- 

 ming a part of the Comm. 

 HERRICK 



Comm. HERRICK 

 Fig. 3. Gasterosieus aculeatus. 

 (Preparation of the Central Institute for Brain research, Amsterdam). 



Ventrallj it mixes, as mentioned, among the fibres of the coni- 

 missura transversa, in two ways. One time it runs iieai'ly horizont- 

 ally towards medial as the most caudal [tart of this comniissure, 

 close to the ventral periphery of the midbrain. Here it soon cannot 

 be traced any further among the commissure fibres. Yet it seems 

 plausible to tne that here if crosses I lie medial line. This I find 

 with Trutta, Syngnathus? '), Ammodyles? '), Mugil, Ophiocephalus, 

 Morone, Osphremenus, Pleuronectes platessa?'), Rhombus, Hippo- 

 glossus?'), Solea?) '), Cyclopterus, Agonus?'), Trachinusand Tetrodon. 



Another time it forms the most dorsal pari of the commissura 

 transversa and crosses directly under the ventricle. I was able to 

 ascertain this course, besides in the cases where it is delusive of 

 the commissura minor (Gasterosteus, Belone and Exocoetus), with 



') The question-marks denote that with these Teleosts I do not find the matter 

 quite clear. 



