126 PHYSIOLOGICAL SERIES. 



The corpora striata are structurally separable into several 

 areas, comparable apparently to the putamen, nucleus caudatus, 

 and globus pallidus of Mammalia. Thy are connected with 

 the nuclei of the thalamus by large and complex basal tracts. 

 The pallium, except for an extension of its cortical area, is 

 essentially the same as in Reptiles; it is in parts extremely thin. 

 The cortico-thalamic tracts are, however, stronger and rnoro 

 numerous than in lower forms, and an important connection first 

 appears in this group between the cortex of the pseudo-occipital 

 lobe and the tectum opticum. Injury to this tract has been 

 shown to interfere with the vision of the opposite eye. Another 

 connection between the cerebrum and tectum opticum (traces 

 of which occur in lleptiles) attains a strong development in 

 Birds. This tract (tractus hippocampo-mesencephalicus) arises 

 from the surface of the median wall of the hemisphere, coils 

 round the cerebral peduncle and terminates in the tectum. Its 

 function is not known. 



The geniculate bodies are enormously developed. The tectum 

 opticum is also highly differentiated, and shows many alternating 

 layers of ganglion-cells and neuropile. The fillet is particularly 

 large, and rises to a great extent as in Fish from a prominent 

 lateral nucleus. The cerebellum is relatively greater than in 

 any vertebrates other than Fish and Mammals. It corresponds, 

 as in the lower groups, with the mammalian vermis. The tract 

 of fibres connecting the cerebellum with the acoustic centre is 

 particularly strong. 



STRUTHIONIFORMES. 



D. 148. The cast of the cranial cavity of a Moa (Dinornis 



w//.<). This, which i- probably a trostworthy representation 



of the brain, differs in several particulars from the brain of 

 living Katite Birds. It is as a whole somewhat more 

 elongated, owin^ mainly to the greater length between 

 tin- anterior extremities of tln hemisphere* and the optic 

 cbiasma. The hemispheres are less arched above, broader in 

 front, and show more marked moial eminences on either 

 side of the dorsal mid-line. The olfactory bulbs are rela- 

 tively large. The optic lobes and nerves are smaller actually 

 than in the Ostrich. The cerebellum has the usual Avian 



