4 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.66 



times instead of about 15 to 20 times in length of intermaxillary 

 and about 6^ times instead of 8 to 11 times in interorbital breadth) ; 

 the intermaxillaries decrease gradually in breadth beyond middle; 

 the palatines leave a considerable portion of the basisphenoid ex- 

 posed when the skull is viewed from below; the malar bone is rela- 

 tively larger (in somewhat the same proportion as the nasal) ; the 

 articular part of the squamosal is, in lateral view, much deeper in 

 proportion to its length ; the coronoid process of the mandible is low 

 and triangular instead of high and irregular in outline; and the 

 groove marking the limit between the angular and articular por- 

 tions of the mandible is better developed, particular!}' on the inner 

 side. 



When contrasted with skulls of the Pike Whale and the Common 

 Finback of eastern North America, that of the Pollack "Wliale is dis- 

 tinguishable by (a) the greater relative length of the rostnmi with 

 regard to the rest of the skull as well as by the narrowness and shal- 

 lowness of the rostrum as compared with its own length (the length 

 of the rostrum, measured in photogi'aphs, from anterior boixler of 

 posterior maxillary concavity to tip is equal to slightly more than 

 twice distance in median line from level of maxillaiy concavity to 

 back of occipital condyles, while in both the other species it equals 

 decidedly less than twice this distance; the gi'eatest width of the 

 rostrmn immediately in front of region where the maxillary border 

 turns abruptly outward is equal to less than half the distance from 

 this widest region to anterior extremity of maxillary, while in both 

 the other species it is equal to more than half this distance; the 

 depth of the rostrum at anterior margin of posterior maxillary con- 

 cavity is contained a little more than five times instead of about four 

 times in distance from anterior margin of maxillary concavity to 

 tip) ; (h) the low, broadly triangular instead of irregularly short 

 ligulate form of the coronoid process of the mandible (compare 

 pi. 3, figs. 2 and 3, with True's pi. 3, fig. 3, and pi. 27, fig. 2.) ; (c) 

 the extension of the palatine bones so far backrvvard that the portion 

 of the basicranial region exposed behind them (when skull is viewed 

 from below) is squarish in outline instead of longer than broad; 

 (d) the presence on the supraorbital portion of the frontal of a 

 noticeable oblique ridge extending outward and backward from re- 

 gion of middle of posterior maxillary concavity to region of middle 

 of orbit (this ridge is present in the two skulls of the Pollack whale 

 examined, one from Florida, the other from Japan; it is absent in 

 the four skulls of the Common Finback figured by True, and in a fifth 

 skull. No. 2375G6, received from Newfoundland in 1904; it is also 

 absent in the four skulls of the Pike Wliale figured by True) ; (c) 

 the conspicuously greater depth and robustness of the articular por- 



