ART. 15. A NEW GENUS OF WHALE FROM MAE^T^.AND KELLOGG. 3 



case. As a result of these features, together with the exchision of 

 the frontals from the vertex of the skull and the position of the 

 nasal, maxillary, and premaxillary sutures, it bears a general resem- 

 blance to the skull of Idiocetus laxatiis^ and is thus somewhat differ- 

 ent from that Agorophius pygmaeiis. A more detailed comparison 

 shows that the skull of Agoj'ophms is con.siderably smaller, pos- 

 sesses projecting condyles and relatively shorter supraorbital proc- 

 esses of the frontals and lacks a sagittal crest; the nasal, premaxil- 

 lary, and maxillary sutures lie posterior to the anterior margins of 

 supraorbital processes, while the apex of the supraoccipital is 

 rounded and not pointed on the vertex of the skull. An additional 

 modilication is shown in the great transverse breadth and propor- 

 tionately short length of the temporal fossae of Parietohalaena. 



The frontals in the skull of Parietohalaena are excluded from the 

 vertex of the skull by the parietals, which meet mesially in the inter- 

 temporal region to form a short sagittal crest. The rostral wall 

 of the cranium is formed largely by the frontals. They are rela- 

 tively short antero-posteriorly and are suturally united along the 

 median line. Either frontal, with its lateral extension — the supra- 

 orbital plate — is constricted mesiallj^; the preorbital projection is 

 rounded, while the postorbital is slender and produced backward. 

 The supraorbital plate of each frontal has a strong sagittal arch, 

 anterior to which the surface slopes forward in a moderate curve, 

 while posteriorly it turns sharply downward. Compared with 

 Getotherium rathhei^ the supraorbital plates are narrower, shorter, 

 and consequent!}^ less curved. 



The parietals, which meet along the dorsal margin of the cra- 

 nium behind the orbits to form a short sagittal crest, are suturally 

 united with the triangular supraoccipital posteriorly and with the 

 frontals anteriorly. Anteriorly the parietal sends forward a thin 

 sheet of bone which, on the left side of the cranium, partially con- 

 ceals the fronto-parietal suture. The imperfect preservation of 

 this surface on the right side exposes the suture for its entire extent. 

 From this it will be seen that it is similar in position to the same 

 suture in the skull of Agorophius pygmaeus? 



The frontals, as remarked above, are overridden by the parietals 

 posteriorly, and the maxillae, premaxillse, and nasals anteriorly. 

 On either side of the median line there is a narrow grooved sinus, 

 with its inner margin elevated above and its outer margin depressed 



1 Van Beneden, P. J., Description des ossements fossiles des environs d'Anvers. Part 

 "i. Annales du Mus6e Royal d'historie Naturelle de Belgique, Bruxelles, vol. 13, pi. 54, 

 fig. 1, 1886. 



- Brandt, .T. F., Untersuchungen ueber die fossilen iiml subfossllen Cetacean Europa'!?, 

 Mem. Acad. Imp. Sci. de St. Petei-sbourg, ser. 7, vol. 20, No. 1, pi. 1, figs. 1-2, 1873. 



^ True, F. W.. Remarks on the type of the fossil cetacean Afforophins pygmaeus 

 (Muller). Special Publ. 1694, Smithsonian Institution, pi. 6, fig. 3, 1907. 



