384 Proceedings of the 



tion with the palate-bone, and the posterior part of the lateral 

 margin is in contact with the pterygoid bone. Its under 

 surface is prominent in the middle line, where it is in contact 

 with the vomer. The vomer is squamous, without teeth, and 

 articulates behind with the basi-sphenoid, and in front with the 

 nasal bone. The under surface of the nasal bone passes on 

 in the same horizontal line as the vomer, and terminates in 

 two broad lobes some distance in front of the pre-frontal. 

 Superiorly it expands backwards on the pre-frontal bone, and 

 articulates with the great frontal on each side of the opening. 

 In the Nilotic species of Malapterurus, as represented by 

 Bilharz, the nasal portion of the cranium is much narrower 

 than in M. Beninensis, and the opening is reduced to a nar- 

 row fissure. The cerebral portion also is much more com- 

 pressed from before backwards, the supra-occipital bone being 

 much less expanded. 



Face Bones. — The intermaxillary bones are united by a 

 symphysis which allows of some motion, and each is articu- 

 lated a little way from its inner extremity to one of the lobes 

 of the nasal bone, without interposition of a cartilage. By 

 this arrangement, although in their natural position they lie 

 in one horizontal plane, they form a decided arch when the 

 mouth is open. They pass outwards and backwards, and their 

 outer extremities are united by ligaments to the hypo-tym- 

 panic bones. They are covered with velvety teeth. The 

 superior maxilla is feebly developed, and does not reach more 

 than half way to the inferior maxilla. It is attached by 

 fibrous tissue to the nasal bone behind the lobe, and by joint 

 to the anterior extremity of the palate bone. The palate 

 bone is small and linear, and passes outwards and backwards 

 to articulate by a facet on its inner aspect with the pre-frontal, 

 and by ligament with the pterygoid bone. The pterygo-tym- 

 panic series of bones are so closely united as to appear like 

 one bone, and are pulled asunder with some difficulty. They 

 lie in a plane approaching the horizontal. The individual 

 pieces are only four in number, — -viz., the epi-tympanic bone, 

 articulating with the skull and with the operculum ; the sym- 

 patic, thick and irregular in shape, and with hollows for 

 mucous tubules; the hypo-tympanic, articulating inferiorly 



