548 Bulletin American Museum of Natural History [Vol. LXVI 



branch of the ethmoturbinals bounded the bones medially. The surface 

 of the frontals with which the nasals were in proximity was in each case 

 slightly concave in accommodation to these bones. 



The lacrimal bone of the right side of the Congo skull is in place, 

 but that of the opposite side is missing, due, obviously, to over-macera- 

 tion. Since Hartlaub found these bones preserved in only one of the ten 

 African skulls examined, and this in a newborn specimen, it appears 

 worth while to note the condition of the lacrimal remaining in the Congo 

 skull. It is, in general, intermediate in size, position, and shape be- 

 tween the type characteristic of inunguis and that invariably occurring 

 in manatus. The bone is at its broadest exposed point 3 mm. in thickness 

 and appears to taper down into its groove between two laminae of the 

 maxillae. Its upper border is nearly in contact with the orbital process of 

 the frontal, while its lower edge touches the edge of the jugal. A tri- 

 angular surface is freely exposed laterally and forms part of the antero- 

 medial wall of the orbital ring. 



The lacrimalia of the inunguis, which I examined closely, resemble 

 those described by Hartlaub. In each case their scalelike nature is 

 evident, and they are quite unlike those of any manatus which I have 

 examined. In most of the manatus studied these bones are in place, and 

 in each case they are essentially similar, large, thick, and more like the 

 same bones in senegalensis than in inunguis. Though the lacrimals are 

 often missing, it is very clear that they had been present, and large, in 

 every manatus skull which I saw. 



The vomers of manatees show strong specific characters in their 

 length. In senegalensis they are always short, extending approximately to 

 the level of the middle of the orbit. In manatus they are long and, 

 except in the newborn, reach to the foramen incisivum or beyond. In 

 inunguis the vomer is intermediate in length between that of senegalensis 

 and manatus, being in the newborn very nearly as short as in the African 

 species, and in old specimens occasionally reaching to within an inch of 

 the incisive foramen. 



Low edges appear on either side of the floor of the nasal chamber 

 anterior to the orbital region. In senegalensis these edges are probably 

 constant. Though Hartlaub concluded from an examination of Surinam 

 specimens that there were no such ledges in manatus, I find them well 

 developed in most, but not all, of the specimens at hand. These ledges 

 are usually present in inunguis but are lightly developed and farther to 

 the rear than in the other species. 



The circumorbital region of the manatees shows something of a 



