Kappers, Teleostean and Selachian Brain. 33 



terior ganglia with the fasciculus retroflexus do not receive any of 

 it, though the somewhat horseshoe-shaped commissure curves 

 backward along the posterior ganglia. Neither in Thynnus, 

 Salmo, Lophius or Gadus was I able to find any asymmetry what- 

 ever of these ganglia, as so distinctly seen in the selachians. 



Under and somewhat caudad from the ganglia habenulae there 

 is a group of small cells extending between the corpus genicu- 

 latum and the wall of the third ventricle, which is somewhat 

 protruded there (Fig. xli), the nucleus thalami anterius, from 

 which a diffuse partly unmedullated tract takes its course, first 

 bending inward, along the lateral wall of the third ventricle, then 

 downward to disappear somewhat before the nucleus rotundus 

 in the same part of the lobi anteriores (pars anterior, Fig. xliv) 

 where the tractus olfacto-lobaris lateralis et medialis terminate. 

 This is the tractus thalanio-lobans, also named tr. thalamo- 

 mammillaris and compared with the tract of ViCQ d'Azyr. 

 Goldstein remarks that the origin of this tract is especially 

 in the lateral parts of this cell mass, which I confirm, and this 

 explains the inward curve which these fibers take. 



In almost the same region the fibers gather which compose the 

 tractus thalamo-spinalis (Figs, xlii, xliii). This passes under the 

 fasc. longitudinalis dorsalis to the medulla. It is evident that it is 

 these fibers which have been described as the thalamic origin of 

 the fasc. long, dorsalis. But they are distinguished from the 

 fibers of the fasciculus by the lighter color which they assume 

 after the Weigert method, so that they cannot properly be said 

 to belong to the thalamic fibers of that fascicle. Moreover, thev 

 get their medullary sheaths later than the true fasciculus. There 

 is, however, no objection in principle to reckoning them with the 

 fasc. long, dorsalis, as this is properly a collective term for longer 

 or shorter longitudinal association fibers. 



It is desirable before proceeding further to give a minute 

 description of the so-called hypothalamus, especially of the lobi 

 inferiores and of the various names which other investigators have 

 given to this region and its constituent parts. 



When following in serial sections the ventral wall of the thala- 

 mus caudad behind the decussatio transversa, we may easily 

 convince ourselves that the hypophysis, which both in Lophius 

 (Figs, xxvi to xxix) and in Gadus (Figs, ix to xi, xxxiv to xxxviii) 

 is turned rather strongly forward, is attached to that part of the 



