METATHALAMUS AND HYPOTHALAMUS. 



375 



It soon separates, however, from its companion and, bending down pos- 

 teriorly at an angle, extends into the tegmentum, posterior to the region of 

 the corpora quadrigemina, where it may be traced until into the ganglia 

 that lie beneath the aquaeductus Sylvii. This is the tegmental iundle of the 

 corpus maniillare. 



8. Ramdn y Gajal and Kdlliker have recently stated that only a single bundle 

 arises from the corpus mamillare, which passes dorsally. The axis-cylinders of this 

 bundle divide at some distance from their point of origin. The anterior branches, 

 or divisions, ended as the tractus thalamo-mamillaris in the nucleus anterior, the 

 posterior as the tegmental bundle in a, nucleus of the frontal tegmentum. Kdlliker 



Fig. 177. — From the dog. Frontal section through the interbrain in the 

 region of the posterior third of the thalamus. For the explanation of the greater 

 part of the figure, see Fig. 169. In comparison with that of Fig. 169 there is 

 to be noted in this section: the ganglion habenulse, in which the taenia dis- 

 appears; the inferior thalamic pedicle; the radiation of the ansa lentiformis 

 into the medulla of the regio subthalamica ; the corpus Luys; and the separa- 

 tion of the superior fillet from the medullary masses lateral and ventral to the 

 thalamus. The pulvinar appears mesial to the corpus geniculatum laterale. 

 Eaub. Bd. Mam., Tegmental mamillary bundle. Mark d. Reg. subthalamica, 

 Medulla of the regio subthalamica. Nucl. E. L. Bdl., Nucleus of posterior longi- 

 tudinal bundle. Ohere HcMeife, Superior fillet. Pars caudalis Gapsulm, etc., 

 Posterior portion of the capsula interna, principally optic radiation. Stiel d. 

 Corp. genie, u. Pulvinar, Pedicle of the corpus geniculatum and pulvinar. Unt. 

 Thai. Stiel, Inferior thalamic pedicle. 



