xo. 2lin. EXTINCT i^lRKXlW DESMOSTYLUS HE8PEliUiS~JJAy. 388 



tebrae, was purchased for the United States National Museum. It 

 has the catalogue number 8181. 



This skull, according to information furnished by Mr. Crawford, 

 was foimd in Miocene shales at the mouth of Spencer Creek, which 

 flows into Yaquina Bay. From Mrs. McCornack I learn that it was 

 about eight miles farther south that was found the fossil seal, Des- 

 matophoca oregonensis, which was described by Professor Condon ^ 

 in 1906. Mr. Crawford found the skull yet enclosed in the rock 

 on the beach, with the palatal surface upward and washed by the 

 waves; and he chiseled it out with some of the matrix adhering. 

 This matrix is exceedingly hard and it adhered closely to the bone; 

 and with difficulty it has been removed since the skull was brought 

 to the United States National Museum. The skull was found in the 

 year 1907. 



The skull has suffered some injuries. The lower jaw is gone. The 

 snout is missing nearly as far back as the rear of the external nares; 

 and just behind this opening some bone is missing as a result of a 

 transverse fracture. A part of the occipital crest is missing on one 

 side. The crowns of all the teeth which had been in use are broken 

 off. Other sHght injuries occur here and there. It is evident that 

 the skull belonged to Marsh's species Desmostylus hesperus and that 

 the Japanese skull already mentioned belonged to a closely related 

 species. The two skulls in many ways supplement each other. The 

 Japanese skull was nearly twice as large as the Oregon specimen. 



The following measurements have been determined : 



Measurements of skull of Desmostylus Jiesperus, in millimeters. 



Extreme length of skull, as preserved 310 



Basilar length, about 360 



From front of foramen magnum to rear of hard palate 110 



From front of foramen magnum to palato-maxillary sutine 175 



From front of foramen magnum to front of basisphenoid 55 



From outside to outside of occipital condyles 109 



Foramen magnum, width from side to side 42 



Foramen magnum, height of 27 



Width of skull from outside to outside of mastoids 190 



Width of skull on zygomatic arch, just over ear cavity 194 



Width of supraoccipital bone 128 



Width of brain case at center of squamosals 123 



Length of parietal bone on midline 55 



Greatest length of parietal 140 



Width of parietal at hinder end 132 



Distance between anterior processes of parietal 7G 



Length of suture between the frontals 106 



From rear of frontals to line joining theii* front ends 150 



Length of suture between the nasals, about IOC 



From outside to outside of nasals 30 



Distance across skull at supraorbital processes Ill 



Width of skull at constriction behind orbits 80 



1 Condon, I'liiv. Oregon Bull., vol. 3, No. 3; Wortman, Science, vol. 24, p. 89. 



