36 'Journal of Comparative Neurology and Psychology. 



which Goldstein has described as tr. tuhero-dorsalis, of which 

 the tr. lobo-cinereus brevis probably represents only a part. 



Regarding the second group, the saccus vasculosus fibers, the 

 finely striped character of the saccus furrows in the teleosts has 

 already been mentioned by Stieda, Ussow and Rabl Ruckhard. 

 Only Ussow mentioned that he considered this to be nervous 

 tissue. GoRONOWiTSCH describes in Acipenser a ganglion in the 

 infundibulum which receives fibers from the saccus and doubtless 

 has secondary connections with higher centers. Johnston 

 mentions in addition to this ganglion one tract for the cyclostomes 

 and two tracts for the ganoids, a centrifugal and a centripetal one, 

 the latter of which originates from the saccus, where its fibers arise 

 from the ciliated epithelium, of whose cells they are the neurites. 

 This tract according to Johnston terminates in the thalamus. 

 The other tract arises between the epithelium. This ciliated 

 epithelium was first described in 1891 by C. L. Herrick in 

 Carpiodes.^ 



Such striped tissue strongly colored by paracarmin is found 

 between the folds of the saccus, partly arising from the epithelium, 

 which is distinguished by strong tufts. The fibers gather at the 

 insertion of this sac upon the thalamus laterally of the connection 

 with the third ventricle and then go under the floor of this ventricle 

 for some distance forward. Where they terminate or what 

 connections they make I cannot say. It seemed to me that they 

 decussate in the median line, but on this matter I shall be able to 

 say more when I treat of the selachians, merely pointing out here 

 that it is an interesting fact in connection with the different origin 

 of the hypophysis and saccus vasculosus that this kind of epithe- 

 lium, as well as these nervous tracts are confined to the saccus. 



To the third group of tracts connecting the nuclei directly under 

 and before the ventriculus opticus with the lobi inferiores belong 

 four systems. 



(i) A group of fibers partly unmedullated and not very compact 

 (Figs, xlii, xliii) which I have already mentioned as the tractus 

 thalamo-lobaris connects the nucleus thalami anterior with the 

 central part of the lobi inferiores. This tract after an inward 



'Some years ago Boeke described sense epithelium in the ventral infundibular wall in larvae of 

 Murena. It seems to me more than probable that it is this which is later found in the saccus, the more 

 so because Johnston told me that in young ganoids he found a part of this saccus epithelium still 

 ending in the infundibulum. 



