:]70 



PKOF. G. ELLIOT S^flTH OX THE 



of the lamina terminalis just above the anterior commissure, and is linked to the ventral 

 surface of the splenium of tiie corpus callosum by a thiu attenuated band, composed of 

 scattered commissural fibres. In the Hapalidae these scattered tiljres are \\aiiliny, 

 so that the psalterium is separated from the corpus callosum l)y a -wide gap ®. In 

 Tarsius there is little or no attenuation of the dorso-caudal part of the psalterium. A 

 ])arallel for this is found in the brain of the Bradypodida^. 



There is a septum lucidum composed of two thin sheets enclosing between tiiein 

 a cavum septi, which is freely open below in tlie Avide interval between the genu of the 



Fit; 46. 



Fig. 4ii. — Tdrsi'.i^ xjiic/i'iiiii. Surface exposed by a mesial sagittal section, x 4. 



Fig. 47. — 'J'ar.iiii.^ s/ii'(iruiii. Diagram representing the mesial surface of the right cerebral hemi-!phere. x 4. 



corpus callosum and the psalterium. In spite of a very generally-expressed belief to the 

 contrary, this is the condition whicli prevails in the vast majority (2)ractically in all) of 

 the Eutheria. 



The anterior comniissure is slightly more than 1 mm. deep and just less than 1 mm. 

 thick (in tiie horizontal plane). For a Primate of such small ditneusions, these measure- 

 ments must be regarded as large, and es2:)ecially so when it is recalled that Tarsi m is the 

 most micvosmatic of Lemurs, and therefore the individual in which such a phenomenon 

 would a. priori be least expected. This means that the neopallial clement in the 



* Vide Joiirii. Anat. and Thys. vul. xxxii. 1*07, fig. i?'i. p. ol. 



