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THE AMERICAN NATURALIST [Vol. XL 



the sutures are largely unclosed; moreover, the rostral cartilage 

 had not ossified so that the thin overarching premaxillae of the 

 rostrum form a long tube nearly closed dorsally except for a slight 

 space where these bones do not quite meet along the median line. 

 The proximal portions of the premaxillse just anterior 'to a line 

 passing across the middle of the blowhole, are nearly flat; they 

 then rise almost perpendicularly to the vertex of the skull and 

 seem to overhang the blowholes but slightly, altli()no:li this refla- 

 tion is somewhat obscured owing to a slight injury. 'I'lic max- 

 illary bones slope dotvmrard from their junction w itli the pivniax- 

 ilhe to the rim of the cranium. In the T.ong Branch cranium, 

 w hich is that of an animal fully adult, the broad proximal portions 

 of the premaxilla? are slightly hollowed in front of the nares, and 

 rising to the summit of the skull, overhang the blowhole by their 

 greatly thickened antero-dorsal edges. In front and at the sides 

 of the nares the maxillaries are elevated as much as 2.5 cm. above 

 the adjacent premaxillaries, so that True's ('85, p. 586) statement 

 in regard to Ziphius and Hyperoodon holds good also in some 

 (Icnree for ^Fesoplodon, namely, that "there appears to be a pro- 

 orosivc exca\ ation or absorption of the bones lying in the median 

 line of tlie upper surface of the beak, accompanied by introvertion 

 of the premaxillffi and a rounding off of the (>xtrcniity of the l)eak." 



In both the Annisquam and the Loiia' HraiK li >kuil> the ri^ht 

 premaxillary is .slightly larger than the h'ft and the riyht nasal 

 opening is more convex in its exterior outline than the left. In 

 both specimens the maxillary and the premaxillary foramina are 

 on practically the same line with relation to the transverse axis of 

 the skull, though in the Long Branch specimen the former is about 

 1 cm. behind the latter. In the Annisquam specimen the max- 

 illary foramen is very large and its opening is below the level of 

 the surrounding parts. It is continued forward as a deep groove 



hx kin- in tli<" skull from Lon- Branch. In each rainus of th"e 

 l.nver jau there is a sin-Ie to..th situated iT. cm. from t\w tip, or 



Grieg ('98) for the two Karmo specimens the large tooth was situ- 

 ated at one third the jaw length from the tip in each. In the Cap 

 Breton specimen, according to P'ischer ('92) the tooth was three 



