8 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 66 



tenth rib articulates with it there. The thoracic vertebrae are, there- 

 fore, formed like those of the Physeteroids and the Ziphioids. 



Transverse processes of the lumbar vertebrae remarkably short, 

 slender, and narrow {Ixacanthus spinosus, Eurhinodelphis cristatus), 

 or long and broad {Eurhinodelphis cocheteuxi^ E. longirostris). 

 Number of lumbar vertebrae probably 11, and of caudal vertebrae 19. 



Number of vertebrae: Cervicals, 7; dorsals, 10 or 11; lumbars, 

 11 ; caudals, 19 = 47 or 48. Scapula very large, broad, and tri- 

 angular, and similar to that of the Delphinoids. Prescapular 

 fossa relatively broad, but the form of the scapula is variable. 

 Humerus similar to that of Physeter^ with the deltoid crest more 

 or less developed; form of the articular head very variable; head 

 of humerus ordinarily oval, extended over upon the external bor- 

 der of the bone. Radius and ulna large, strong, about as long as 

 the humerus. Olecranon very large, and strongly notched below. 

 Of the carpal bones the following are known : Radial, intermedium, 

 and cubital which are ankylosed (old individual). The phalanges 

 are present. The largest specimens of the largest species {Eurhin- 

 odelphis cocheteuxi) may have attained a length of 4 or 5 meters. 



INDIVIDUAL 1 

 EURHINODELPHIS BOSSI, new species 



Type. — Cat. No. 8842, Section of Vertebrate Paleontology, 

 United States National Museum. This specimen consists of a com- 

 plete skull with the exception of the ear bones, both lower jaws, 

 sixteen vertebrae, ten ribs, an imperfect scapula, a humerus, and 

 part of the sternum. 



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

 40' north, and longitude 76° 40' west, about 2 miles south of 

 Chesapeake Beach, on the western shore of Chesapeake Bay, Cal- 

 vert County, Maryland. Shown on Patuxent Quadrangle or 

 Patuxent Folio, No. 152, United States Geological Survey. 



Horizon. — The specimen was discovered and excavated by Nor- 

 man H. Boss in August, 1918. It was dug from the cliff above the 

 oyster shell band. The specimen, apparently, was embedded in 

 Shattuck's zone No. 5 of the Calvert Miocene formation of Mary- 

 land. 



SKUIX 



Dorsal view. — Although the outlines and relations of the bones 

 forming the dorsal surface of the slmll (pi. 1) at first glance are \ 

 strongly suggestive of Schizodelphis^ there appear to be some well- 

 marked differences. In the Schizodelphis skull the exposed portions 

 of the frontals on the vertex are considerably larger than the paired 

 nasals, and the teeth are swollen near the base of the crown and 

 rather robust. Conversely, in the Eurhinodelphis skull the paired 



