RECENT INVESTIGATIONS ON THE STRUC- 

 TURE AND RELATIONS OF THE 

 OPTIC THALAMI. 



Henry Russell Pemberton, M.A., B.S., 



University Fellow in Biology, Princeton College. 



There has been much written of late concerning the optic 

 thalami and their connection with neighboring structures 

 in the brain. To present all the various views held with re- 

 gard to these important basal ganglia would be tedious, 

 while to discuss them fully within the compass of these 

 pages would be impossible. Consequently, let us confine 

 ourselves to the matter that has been published during and 

 since the year 1885, filling up with discoveries made before 

 that date such gaps as may arise, because during the last six 

 years all structures herein brought to notice have not 

 received equal share of attention. 



A precise description of the two structures in the brains 

 of mammals called the optic thalami, would at this stage of 

 neurological research be unnecessary. The structure and 

 relations of the epiphysis are not here discussed. So much 

 has been written recently concerning this subject, that a 

 further setting forth of it is not necessary. The reader is re- 

 ferred to Cattle's excellent article (Archives de Biologie, 

 Tome III, 1882). 



The fishes are characterized by a small development 

 of the thalamencephalon, and in them we can recognize 

 structures corresponding only to parts of the thalamus in the 

 higher vertebrates, e.ff., that part of the thalami in the mam- 



