ARREST OF DEVELOPMENT. 45 



the brain. The cerebrum is very small ; its anterior lobes 

 are completely fused. The middle lobe of the cerebellum 

 and the corpora quadrigemina are proportionately very 

 large ; the latter are not covered by the cerebrum. 



Hunterian. 



167. The head of a similar foetal Pig. The roof of the skull has 



been removed. The cerebral lobes are completely fused 

 in front. The whole brain scarcely fills a quarter of the 

 cranial cavity. Hunterian. 



168. A similar preparation, but the eye is apparently very de- 



fective. The cornea and lens seem to have been arrested 

 in their growth. The cornea is conical. Hunterian. 



169. A similar specimen with the side of the face dissected to 



show the form of the skull, the superior maxillary bone, 

 and pterygoid processes. The zygoma and the ascending 

 ramus of the mandible have been removed. The pro- 

 longation of the frontal bones into the proboscis is well 

 seen in this preparation. Mus. Brit. 



170. The head of a foetal Pig with cyclopia, dissected, to show 



the condition of the brain and nerves. The distribution 

 of the ophthalmic branch of the fifth to the proboscis, and 

 the superior maxillary nerves to the maxillae, is well seen 

 on the right side of the head. The brain is exposed on 

 the left side. The small hemispheres are fused together. 

 The"' corpora quadrigemina and the cerebellum are not 

 covered by the cerebrum. 



171. A dissection of the head of an Indian wild Boar with simi- 



lar deficiencies. 



The upper preparation consists of a section of the head. The 

 cavity of the proboscis extends back to the cranial bones and con- 

 tains a cartilaginous fold, probably the inferior spongy bones. The 

 lower preparation shows TiHe maxilla and teeth, the pterygoid and 

 styloid process, the middle ear and its ossicles, together with the 

 gustatory and hypoglossal nerves. 



172. A foetal Boar with similar deficiencies. There is consi- 



derable inequality of development on the two sides, with 

 consequent dislocation of the eye. Hunterian. 



173. A foetal Hare with similar deficiency. The frontal pro- 



boscis is comparatively small. 



Presented by A. Newton, Esq. 



