10 BULLETIN 73, UNITED STATES NATIONAL MUSEUM. 



pterygoids. The inferior surface of the pterygoids is convex on the side adjoining 

 the lateral free margin (PI. 4, fig. 2). 



This skull is peculiar in that there is no very distinct basirostral groove and that 

 the basirostral ridge, as already stated, extends forward only about 90 mm. Below 

 this ridge is a shallow broad groove which narrows rapidly forward and can be traced 

 to the extremity of the beak, where it broadens out somewhat (PI. 7, fig. 2). 



Wliile tliis skull agrees in size and in many of its proportions with similar skulls 

 of M. hidens, it differs from that species and agrees with M. densirostris in the breadth 

 across the anteorbital region, in the depth of the beak and its shape at the base, in 

 the shape of the premaxillaj both distally and proximally, in the direction of the 

 maxillary foramen, and the shape of the maxillary bone in front of the same, in the 

 occupation of the base of the maxillary notch by the anterior end of the malar, in the 

 absence of any distinct maxillary ridge above the notch, in the forward extension of 

 the palatines, and in the shape of the foramen magnum. 



Flower states that there is a deep basirostral groove in M. densirostris, <^ but 

 neither the figure in Gervais' Zoologie et Paleontologie Fran^aise,'' nor that in Van 

 Beneden and Gervais' Osteographie des C^taces,'^ shows such a groove. The con- 

 formation of the base of the rostrum appears to be about the same as in the Annis- 



quam skull. 



In regard to difTerences between this skull and those of J\I. densirostris it should 

 be stated that in the latter the premaxillary foramina are situated farther apart, and 

 that the maxillary foramina are situated considerably in advance of those of the 

 premaxillic instead of nearly in line with them. 



The Annisquam skull approaches M. europmus in several characters, but these 

 are such as europmis shares with densirostris. The principal ones are the breadth 

 of the maxilla; in front of the orbits, the presence of the malar in the base of the 

 anteorbital notch, and the convexity of a part of the inferior surface of the pterygoids. 

 Dr. Glover M. Allen has given an account of the exterior, skeleton, and teeth of 

 this specimen, from which the following particulars are extracted:"^ 



Reo-arding the Annisquam specimen no color notes were taken, but from a few small photographs 

 in the possession of the Boston Society of Natural History, it appears evident that the ventral portion 

 wa.s of a lighter tint, and in one of the views a few oval whitish spots are seen on the side a trifle behind 

 the middle ])ortion of the body. Another view shows the convexity of the posterior margin of the flukes 

 at the median point, as well as the prominent dorsal fin. The lower jaw protruded slightly beyond the 

 upper. Measurements of this specimen, as noted by Professor Hyatt, are as follows: Total length, 12 

 feet 2 inches; from anus to bight of flukes, 3 feet 4 to 6 inches; across flukes, 3 feet 1 inch; from tip of 

 rostrum to angle of mouth, 1 foot U inches. The gijlar furrows were noted as about 10 inches long and 

 from i to i an inch deep. 



The teeth of the Annisquam specimen barely projected above the alveoli of the jaws and are sharply 

 mucronate. The basal portion of each, however, is more like that of the male's tooth [31. europxus] 

 in the slightly convex posterior outline and the forward extension of the anterior angle. * * * 



The Annisquam skeleton has 4.5 vertebrae. Four of the seven cervicals are fused. The atlas, axis, 

 and third cervical are firmly anchylosed throughout, sa\e for the lateral foramina for the passage of the 



"Trans. Zool. Soc. London, vol. 10, 1878, p. 418. 



b Second ed., plate 40, fig. 4. 



<• Plate 25, fig. 2. 



d Amer. Nat., vol. 40, IS'JO, pp. 3G3-370, fig. 3 (tooth, nat. size); fig. 4 (sternum). 



