2 PROCEEDINGS OF THE NATIONAL MUSEITM. vol.63, 



ity of post orbital projection of supraorbital plate; condyles small 

 and borne on short necks ; exoccipitals directed obliquely downward 

 and backward, with their lateral margins projecting beyond level of 

 articular faces of condyles; jugular incisure deep and rather broad; 

 angle formed by anterior margin of squamosal and its zygomatic 

 process external in position. 



The periotic exhibits a marked modification of the type present in 

 skulls of RhacManectes glaucus^ Megaptera nodosa^ and Cetotherium 

 rathkei. The labyrinthic region is strongly compressed, so much so 

 that the cerebral aperture of the facial canal, the internal acoustic 

 meatus, and the aperture of the aquaeductus cochleae open on the 

 dorsal face of this bone and not on the internal face as in living 

 whalebone whales. The tympanic and periotic exhibit only minor 

 modifications of the type found in Idiocetus Icvxatus. 



PARIETOBALAENA PALMERI, new species. 



Type. — Cat. No. 10668, Division of Vertebrate Palaeontology, 

 "United States National Museum. This specimen consists of a cranium 

 in a fair state of preservation; the nasals, jugals, and lachrymals, 

 as well as the rostrum and its component parts, the maxillae, pre- 

 m axillae, and vomer are missing. Both periotics are preserved in 

 place. One imperfect tympanic also belongs with this skull. 



Type locality. — The occurrence is as follows: Near latitude 38° 

 35' N., longitude 76° 31' E., on the western shore of Chesapeake Bay, 

 1 mile above Dares Wliarf, Calvert County, Maryland. Shown on 

 Patuxent Quadrangle or Patuxent Folio No. 152, United States 

 Geological Survey. 



Horizon. — The specimen was discovered and excavated by William 

 Palmer on August 14, 1913. It was dug from the cliff 3 feet above 

 the beach and about 8 feet above the wide shell stratum (Shattuck's 

 zone 10), which is at this point well under the beach level; thus, it 

 was found at about the center of zone 11, both strata being here 

 much thicker than further northward. It may thus be assigned to 

 Shattuck's zone 11 of the Calvert Miocene formation of Maryland. 



DESCRIPTION OF THE SKULL. 



Dorsal vieiv. — In general form the skull of Parietohalaena is 

 directly intermediate between Cetotherium and Idiocetus. The 

 most obvious features of this skull (pi. 1) are: The marked inter- 

 temporal constriction of the cranium and the triangular shape of 

 the supraoccipital, which is broad at the base and whose sides curve 

 obliquely upward, forming an apex on the vertex. The form and 

 dimensions of the bones comprising the rostrum are unknown. The 

 f rentals and squamosals project strongly from the sides of the brain 



