68 ALUS. [Vol. XVIII. 



The Vomer {VO) has a short, stotit, anterior portion, or head, 

 and a long, thin posterior portion, or body, which ends in a long 

 and slender point. On each of its lateral edges, immediately pos- 

 terior to the head of the bone, there is a flat, thin, lateral process, 

 projecting laterally, upward and backward. The process occupies 

 about one third the length of the edge of the body of the bone, and 

 its dorso-posterior end, which is frayed, connects by suture with 

 the lower end of the ventro-anterior arm of the X of the pre- 

 orbital ossification. The dorso-anterior edge of the process lies 

 immediately below, or slightly overlaps, the ventral edge of the 

 ethmoid, its anterior end lying immediately below the cartilage that 

 caps the ventro-lateral process of the same bone. 



The head of the vomer is formed by two stout, condylar proc- 

 esses directed downward, forward and laterally, and having on 

 their outer ends large and somewhat kidney-shaped articular sur- 

 faces, which are presented laterally, forward and slightly upward 

 rather than downward. They articulate indirectly, on each side, 

 with the corresponding maxillary bone, being separated from that 

 bone by a dense biconcave pad of fibrous tissue. The articular 

 surface of the vomer thus lies ventro-mesial, or ventro-postero- 

 mesial to the articular end of the maxillary, instead of ventral and 

 ventro-anterior to it, as in Auiia, and the bone has no articular rela- 

 tion whatever with the palatine, that bone articulating with the 

 ventro-lateral process of the ethmoid, and with the external surface 

 of the maxillary. 



Between the convex, mesial edges of the articular surfaces of 

 the vomer, the ventral and ventro-anterior surfaces of the bone 

 are concave. Along each lateral edge of the ventral part of this 

 surface, parallel to and but slightly mesial to the hind ends of the 

 infero-mesial, curved edges of the articular surfaces, there is a 

 short row of small, sharp teeth, usually three or four in number. 



The dorsal edge of the anterior end of the vomer is sharply 

 notched in the middle line, between the anterior-superior ends of 

 the articular heads of the bone, the notch receiving the median 

 process of the beak of the chondrocranium. The lateral processes 

 of the beak fit into V-shaped depressions on the dorsal surface of 

 the vomer immediately posterior and lateral to this notch. With 

 this part of the chondrocranium the vomer is intimately con- 



