304 THE ANATOMY OF VEETEBEATED ANIMALS. 



(continuous throucrli the foramen of Munro with the third 

 ventricle), which is little more than a fissure between the 

 very thin inner wall of the lobe and its thick outer part, 

 which contains the corpus striatum. The corpora striata 

 are united by an anterior commissiire, which is not of large 

 size. The thinning of the inner wall of the lobes, from the 

 margin of the foramen of Munro backwards, which gives 

 rise to the fissure of Bichat in the Mammalia, extends for a 

 very short distance in the Sauropsida, even in birds. 



The olfactory lobes are usually elongated, and contain 

 ventricles continuous with those of the prosencephalic 

 hemispheres. 



In all Sauropsida the motor nerves of the tongue pass 

 through a foramen in the ex-occipital bone. Hence, twelve 

 pairs of cranial nerves are present, except in the Ophidia, 

 which possess no spinal accessory nerve. 



The lateral cutaneous branches so generally sent to the 

 trunk by the pneumogastric in the Ichthyopsida are absent, 

 but the pneumogastric gives a recui-rent branch to the 

 larynx. The third, fourth, and sixth nerves arise quite 

 indefiendently of the fifth. 



The sympathetic is well developed, except in the Ophidia, 

 where it is not distinct from the spinal nerves, in the 

 greater part of the trunk. 



The Ophidia, many Sauria, and Aves, possess nasal 

 glands, which, in birds, attain a large size, and lie more 

 usually upon the frontal bone, or in the orbits, than in the 

 nasal cavity. 



The eye, rudimentary in some Ophidia and Lacertilia, is 

 Tisually large ; and, sometimes, as in many birds and in the 

 extinct Ichthyosauria, attains very great absolute and rela- 

 tive dimensions. 



In the Ophidia and some Lacertilia (the Amphishcenoidea, 

 some Scincoidea, all Ascalobota), the integument is con- 

 tinued over the eye, and becomes transparent. These 

 reptiles are commonly said to possess no eyelids ; but it 

 must be remarked that this is not true of them in the 



