ART. 15. A NEW GENUS OF WHALE FROM MARYLAND — KELLOGG. 9 



Greatest antero-posterior diameter of supraorbital process of frontal (tip mm. 



of preorbital projection to tip of postorbital projection) 115 



Distance from apex of supraoccipital to level of anterior margins of 



frontals 138.5 



Greatest breadth of skull -across zygomatic processes of squamosal 332 



Vertical height of skull (basisphenoid to apex of supraoccipital) 133 



Least breadth of cranium between temporal fossae 99 



Distance from vertex to upper margin of foramen magnum (estimated) __ 147 



Height of foramen magnum (estimated) 37 



Breadth of foramen magnum 40. 5 



Greatest distance between outer margins of occipital condyles 86. 5 



Greatest diameter of left condyle 65 



Distance across skull between outer margins of exoccipitals 225. 5 



Distance between tip of-postglenoid and tip of zygomatic process of left 



squamosal 115 



Distance between tip of left zygoma (as preserved) and postorbital pro- 

 jection of frontal 36.5 



Distance between tip of preorbital projection of supraorbital process of 



frontal and tip of postglenoid process of squamosal 242 



Greatest breadth of basioccipital across lateral protuberances 75. 5 



Distance between anterior margin of foramen magnum and anterior mar- 

 gin of basisphenoid 126 



PERIOTIC. 



The body of the right periotic (pi. 5, fig. 1) is irregularly quad- 

 rangular, although the internal margin is indented by a deep V- 

 shaped depression. It differs greatly from the periotics of such 

 whalebone whales as RJiachianectes glauciis^ Megaptera miocaena^ 

 and Cetotherium TatKkei^ or from Metopocetus durinasus^ and ex- 

 hibits a close resemblance to that of Idiocetvs laxatus? The struc- 

 tural peculiarities of the periotic of Idiocetus laxatus are of the 

 same general type as this fossil periotic. The differential features 

 of the Parietohalaena periotic consists of a shorter and more robust 

 posterior process and a larger internal acoustic meatus. The periotic 

 of Heterocetus hrevifrons ^° might be confused with this form, but 

 in the latter the apex of the labyrinthic region is more pointed and 

 the groove above external aperture of the aquaeductus vestihuli is 

 much narrower. The labyrinthic region is strongly compressed, so 

 much so that from a dorsal view (pi. 5, fig. 2) it appears to be 

 crushed against the prootic. The margins of the labyrinthic region 

 are well defined on the dorsal face. The dorsal surface of the pro- 

 otic is closely applied to the petrous portion of the squamosal, and 

 the anterior margin is in contact with the pterygoid process of the 

 alisphenoid. 



1 Kellogg, R,, Proc. II. S. Nat. Mus., vol. 60, No. 2435, text figs. 1, 3, 6, 7, 1922. 



« Brandt, J. F., Mem. Acad. Imp. Sci. de St.-Petersbourg, ser. 7, vol. 20, No. 1, pi. 3. 

 fig. 2, 187.3. 



" Van Beneden, P. J., Description des ossements fossiles des environs d'Anvers. Part 5. 

 Annales du Mus6e Royal d'histoire Naturelle de Belgique, Bruxelles, vol. 13, pi. 54, figs. 

 3-4, 1886. 



i» Van Beneden, P. J., Idem, vol. 13, pi. 26, figs. 2-5. 



