1888.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 279 



bone is present in all the genera and species of Albatrosses examined 

 by nie, as well as in Thalassiarche chlororhyncha, as mentioned by Bein- 

 hardt. In the Oceanitidce, in Proccllaria, and Cymochorea, as well as 

 Paction and Pagodroma, its place is taken by a narrow ligament, with 

 a small, more or less ossified nodule of bone lying in it, only connected 

 by connective tissue with the surrounding bones. In Acipetes, Prion, 

 PuffinuS) Majaqueus, Adamastor, and (Estrelata it is small and delicate, 

 articulating with the lacrymal above and ending freely (in the cleaned 

 skull) below. 



"It is interesting to observe that a very similar bone, both as regards 

 shape and position, occurs in the genus Fregata, as already pointed out 

 by Bernhardt, whose observation I have been able to verify. But it 

 also occurs in forms so different from these, as the Musophagidce, many 

 Cyculidce, Chunga, and Cariama, as well as in some Laridce and Alcidw, 

 so that its presence is obviously of no particular taxonomic value. Pro-' 

 fessor Parker informs me that its precise morphological significance is 

 at present rather uncertain." (Coll. Scientif. Mem., p. 415.) 



So prominent and jutting are the bony chambers which contain the 

 organ of hearing upon the internal lateral aspects of the cranial cavity 

 that the oval fossa, which harbors the hind brain in life, is far deeper 

 than we would have any reason to suspect from an inspection of the 

 posterior external view of the skull alone. This applies almost with 

 equal truth to the fossae lodging the other lobes. 



The usual arterial and nervous foramina open here in nearly the same 

 positions as we find them in birds generally. 



Fio.ld 



FLrj<l7< 



Fig. 16. Left lateral view of vomer, pterygoid, and part of palatine of JHomsdea albatrus. 



Fig. 17. The same bones viewed from above; v, vomer; pi, palatine (broken away in front): pt, 

 pterygoid. Both figures life size. By the author, from another specimen presented him by Dr. T. H. 

 Bean. The little foot on the anterior end of the vomer makes its appearance in the median cleft just 

 beyond the maxillo-palatines. as seen in Fig. 14. 



