206 MEMOIRS OF THE CARNEGIE MUSEUM 



Although morphologically very much alike, the palatines in Fregata fuse together 

 where they come in contact with each other posteriorly, which is not the case in any 

 Albatross ever examined by me. The ascending and descending laminae are not so 

 powerfully developed as they are in the Albatrosses, but in Fregata we still find the 

 broad, horizontally flattened anterior moieties of the palatines, with the mesial, 

 elongated and narrow interval separating them. At the fore part of this we like- 

 wise see the maxillo-palatines, similarly separated, with their external borders and 

 surfaces accurately fused with the contiguous bones. Between them, we discover 

 the sharp apex of the extremely slender, and long, and free, and curved vomer of the 

 Man-o'-war Bird, so very suggestive of being an extreme modification of that element 

 as we found it to exist in Diomedea. (See Figs. 16 and 17, in my memoir on the Oste- 

 ology of the Tubinares and Steganopodes, P. U. S. N. M., 1888, p. 279, for the vomer 

 in an Albatross.) 



The postero-external angle of a palatine in Fregata is inclined to be somewhat 

 produced, whereas in the Diomedeidse as a rule that angle is rounded off (PI. 

 XXIX., Fig. 48). 



Upon examining the mandible in Fregata it also presents a number of characters 

 it has in common with that bone in Diomedea. In form it is a long V-shaped struc- 

 ture, with truncated postero-articular ends. The rami are strong and thick; the 

 ramal vacuities are closed in; the rather .meager symphysisis decurved and sharply 

 pointed at the apex. Along the superior margin of either dentary portion, runs a 

 distinct groove ; these borders being cultrate in the Albatross, and the aforesaid 

 groove being conducted down upon the mesial aspect of the dentary element, where 

 it is far less pronounced, and its nature not so marked. The mesial aspect of either 

 dentary part of the jaw in Fregata is also deeply grooved for nearly its entire length ; 

 this last groove is but faintly developed in Diomedea, and that only at the anterior 

 third of the bone (PL XXIX., Fig. 47). 



Fregata has a more pneumatic mandible than Diomedea, and the foramen at 

 either articular end is, in the former genus on top of the mesial process, while in the 

 latter it is situated at the base of the obliquely-disposed, deep, central concavity, or, 

 in other words, that concavity which is intended to accommodate the inner large 

 articular facette on the quadrate. It is single and circular in either case. 



Fregata has a very simple skeleton as to its hyoidean apparatus, for the fore part is 

 considerably aborted, while behind all the elements do not ossify. The small glosso- 

 hyal is performed entirely in elementary cartilage, and only the diminutive cerato- 

 hyals, which are distinct from each other, ossify. The short, rather bulky, first 

 basibranchial ossifies, but there is no sign of a second one. Of the thyrohyal ele- 



