BEAKED WHALES, FAMILY ZIPHIID.E — TRUE. 5 



2 inches, straight); (2) the adult male obtained at Brodie House, Scotland, in 

 1800, and recorded by Sowerby" (length 16 Teet). The length of the skull is not 

 given for either of these specimens. The adult male obtained at Rugsund, Norway, 

 in 1901, and recorded by Grieg,'' was only 15 feet 1 inch long, but some of the 

 measurements of the skull are as large as, or even a little larger than, those of the 

 Nantucket skull. The total length of the skull was not given, as the end of the 

 beak was lacking. 



Grieg's figures of the Rugsund skull afford a very satisfactory basis for com- 

 parisons between that specimen and the Nantucket skull (PI. 1, fig. 1). Both 

 skulls show the comparatively narrow frontal region, the moderately developed 

 tubercle anterior to the anteorbital notch, and the low maxillary ridge, which are 

 characteristic of the species. In both skulls the anterior prolongation of the eth- 

 moid is lanceolate and flat, but in the Rugsund skull the apex is truncated. In 

 the latter also the posterior end of the mesirostral ossification is divided into three 

 longitudinal sections by two lateral and somewhat divergent grooves, while in the 

 Nantucket skull there is only a single median groove. These differences may safely 

 be regarded as individual. Toward the distal end the surface of the ossification in 

 the Nantucket is pitted and irregular and descends much below the level of the 

 premaxillfe. It ends distally at the same point with the vomer. In this skull the 

 proximal end of the premaxilla^ and adjoining plate of the maxillse are somewhat 

 less reflexed than in the Rugsund skull. The shape of the superior margin of the 

 supraoccipital is alike in botli. 



There are no well-defined differences in the relative thickness of the beak at the 

 base or in the form and position of the visible portion of the palatines, but in the 

 Nantucket skull the mass of the combined frontal and lachrymal anterior to the 

 orbit is less rounded and more triangular than in the Rugsund skull. The temporal 

 fossae also have a postero-superior angular enlargement not seen in the latter. 



In the Nantucket skull the rostral portion of the premaxillse is high and at the 

 distal end vertical. The superior profile is somewhat convex, and the superior free 

 margin rounded proximally, but sharp distally. The least distance between the 

 free margins is 10 mm. 



The pterygoids are cut off from the maxillse anteriorly by a very narrow band 

 of the palatine, which connects with a broad band externally and a lanceolate seg- 

 ment internally. The inferior pterygoid ridges diverge anteriorly. The broad sur- 

 face internal to them is concave. The external border .of the pterygoid sinus is 

 nearly straight. An elongateil, fusiform section of the vomer is visible on the infe- 

 rior surface of the beak at the middle for a distance of 158 mm., and a small lozenge- 

 shape section, ill defined, is visible between the pterygoids and palatines. (PI 4. 

 fig. 1.) 



The expanded anterior end of the malar is rhomboidal in form, with an externa! 

 free margin 11 mm. long. Anterioi-ly it does not form part of the margin of the 

 anteorbital notch. 



"Trans. Linn. Soc. London, vol. 7, 1804, p. 310. 

 f> Bergena Mus. Aarb., 1904, no. 3. 



