585 



itself with the internal capsule so as to reach the dorsal area of the 

 neopallium by a shorter and slightly less circuitous course (fig. 2). 



This peculiarity was represented in the drawings of sections 

 through the brains of Macrojms and P/iascolomys, in 1865, by the late 

 W. H. Flower'. It was more distinctly shown in a diagram ^ illustrat- 

 ing a coronal section through the brain of a Derbian Wallaby which 

 was published 27 years later by Johnson Symington. Two years 

 later I placed on record the observation upon it, that "in Phalangista 

 [Triel/oswus vulpecula] a bundle of anterior commissure fibres proceeds 

 to the cortex via the internal capsule, in addition to the external cap- 



o.d'. 



cp.e. 



Fig. 2. Transverse section through the two cerebral hemispheres of the same in the 



plane a, /; (fig. 1). X 3. c.d., commissura doraalis. c.v., commissura ventralis. cp. e., 



capsula externa, f.a., fasciculus aberrans. 



sule"'*, and in the same place noted an analogous arrangement in 

 various species of Macropus. 



In 1897 Theodor Ziehen recorded* the presence of such fibres in 



1 On the Commissures of the Cerebral Hemispheres of the Marsupialia ami 

 Monotremata, as compared with those of the Placental Mammals. Phil. Trans., 

 Vol. 1.5.5 (1865) p. 633. 



2 The Cerebral Commissures in the Marsupialia and Monotremata. Journal 

 of Anatomy and Physiology, Vol. 27. 1892. fi^. 3. p. 81. 



'' Preliminary Observations on the Cerebral Commissures. Proc. Linn. Soc. 

 of N. S.W., 1894. p. 647—648. 



* Das Centralnervensystem der Monotremen und Marsupialia (Semon's Zoolo- 

 gische Forschungs-Reisen in Australien). Denkschr. Medic.-naturwiss. Gesellsch. 

 Jena. Vol. 6. Lf. II and IV, 1S97— 1901. 



40 



