Ixii Journal of Comparative Neurology. 



■ ness [ventricular cinera] from the true grey matter of the diencephalon. 

 Two tracts arise from it, the ventral decussation of the central grey and 

 the tractus ad decussationem infundibuli, the latter ending after decus- 

 sation in the wall of the saccus vasculosus. 



The real origin of most of the diencephalic tracts is the dorso-caudal 

 region of the pars infundibularis. Thence springs the fasciculus longitu- 

 dinalis, which can be followed with a clearness hitherto unattained from 

 its origin to the ventral column of the cord. Laterad and caudad of it 

 arises the processus ad cerebellum, which, after passing a short distance 

 on the basis pass into the decussation of the cerebellar peduncles and 

 thence to the cerebellum. 



The diencephalon of amphibians was also studied by various methods 

 and in numerous species. Careful studies of the infundibular region 

 especially were made. The author finds the following connections with 

 the prosencephalon : (i) the basal prosencephalic bundle, as in Selachii; 

 (2) tract to habenuhi; ; (3) diencephalic root of the olfactory; (4) doubt- 

 fully, a decusatio post-optica behind the chiasm corresponding to the 

 mantle bundle of Selachii. From the grey matter of the diencephalon 

 arise tracti thalami anterior and posterior from the two ganglia of that 

 region. The connections of the habenulre are as in Selachii. 



The paper deserves careful study. Respecting the mantle bundle 

 and the ventral commissures of the diencephalon the results seem to be 

 unharmonizable with those of the present writer derived from a detailed 

 study of the teleosts and amphibia. The basal prosencephalic bundle 

 contains the present \vriter's fornix tract. The figures are diagramatic 

 but very useful. The remaining installments will be awaited with in- 

 terest. 



The Nervous System of Pseudoscorpions.i 



The central nervous system, which lies in the cephalic part of the 

 cephalothorax, consists, as in all Arachnida, of a supracesophagal gang- 

 lionic mass which is so closely connected with the thoracic ganglia that 

 lateral commissures are practically absent. The two lobes together con- 

 stitute an oval mass about .5 mm. long and .4 mm. in greatest width. Of 



1. H. Cronebero. Beltrag zur Kenntniss des Banes der Pseudoscorpion. BuL 

 Soc. imp. des Naturalistes de Moscow, 1S,S8, 3. 



