64 ALUS. [Vol. XVIII. 



To that end of the cranium it is attached, not only by general 

 fibrous tissues, but also, on each side of the head, by the ethmoido- 

 maxillary ligament and the fibrous or semi-ligamentous nasalo- 

 maxillary band. The ligament arises, as already stated, from the 

 dorso-lateral process of the ethmoid, or from the median ridge of 

 the ethmoid in front of the process. The semi-ligamentous band 

 arises from or near the anterior end of the nasal bone. Both liga- 

 ment and band are inserted, in whole or in part, on the outer 

 surface of the maxillary, on or near the lateral process found 

 near the ventral edge of the anterior end of that bone, and thus one 

 or both of these structures seem to represent, in Scomber, the 

 fourth division of the levator maxillae superioris muscle of Amia. 

 The band has often much the character of tough subdermal tissue. 

 When the mouth is closed the shanks of the maxillary and pre- 

 maxillary pass upward internal to the lachrymal and are entirely 

 hidden from view by that bone, the lower edge of the lachrymal 

 thus forming, in the recent state, the apparent edge of the upper lip. 

 The maxillary lies dorsal to the premaxillary, its ventral edge 

 slightly overlapping laterally the dorsal edge of the latter bone. It 

 is entirely without teeth, and a slight fold in the dermal tissues of 

 the lip extends upward between it and the premaxillary. Another, 

 but much more important fold extends upward between the outer 

 surfaces of the maxillary and premaxillary and the inner surface 

 of the lachrymal, this fold extending from the hind end of the 

 mandible nearly to the anterior end of the snout. The hind ends 

 of the maxillary and premaxillary are both slightly enlarged and 

 flattened, and are bound together by dermal tissue. In the recent 

 state, when the mouth is closed, they lie in a depression on the 

 outer surface of the lower jaw, near the hind end of its dorsal 

 edge. They are strongly but loosely connected with the mandible 

 by dermal tissue, by which they are pulled downward and forward 

 when the mouth is opened. The same tissues tend to pull them 

 back in place when the mouth is closed, but, in addition to this 

 indirect action, the adductor mandibulse muscle acts directly upon 

 the two bones by a long tendon that arises from the lower, ante- 

 rior end of the muscle and is inserted on the external surface of 

 the maxillary, at its ventral edge and not far from its anterior end. 



