A NEW FOSSIL PORPOISE FROM MARYLAND. 1C7 



with both halves of the mandible, 5 teeth in position in the upper jaw and 8 in 

 the lower jaw, and 30 additional detached teeth; one tympanic bone and one 

 periotic; the larger portion of the hyoid; six cervical vertebrae and the centrum of 

 a seventh; 9 thoracic vertebrae, 6 lumbar vertebrae, and 5 caudals; 1 about 25 

 detached epiphyses of vertebrae; 2 chevron bones; more than 17 ribs, some of 

 them complete; one complete scapula and fragments of the other, both humeri 

 and radii, and one ulna; a number of miscellaneous fragments. 





Skull. 

 The skull (PI. XVII, figs. 1-3; PL XVIII, fig. 1) in its present condition is 



360 mm. long, and 171 mm. broad between the outer surfaces of the postorbital 

 processes. It has been crushed downward so that the end of the zygomatic 

 process nearly touches the top of the orbit. The end of the rostrum is nearly 

 complete, but portions of the premaxillse and of the left maxilla near the distal 

 end of the rostrum are lacking. The right maxilla is much fractured near the 

 distal end. Otherwise, the upper surface of the skull is nearly intact, except 

 that the right orbital region is somewhat fractured and a little defective. 



The inferior surface of the skull, though much fractured and distorted, 

 especially proximally, is nearly complete, the principal parts lacking being por- 

 tions of the palatal and pterygoid bones, and the proximal ends of the malars. 

 One earbone is lacking. The posterior surface of the skull is much fractured 

 and depressed, but nearly complete, 



Superior Aspect (PL XVII, fig. 1).— The rostrum is a little longer than the 

 brain-case, broad at the base and tapering gradually to the apex. The pre- 

 maxillae at the proximal end touch the nasals, being wedged in between them 

 and the reflexed postero-internal border of the maxillae. Opposite the nares, 

 their internal border is concave and their external border convex. They are 

 nearly plane in this region and very broad, the greatest breadth of each about 

 equalling the portion of the frontal plate of the maxilla which lies external to it. 

 The premaxillary and maxillary foramina are almost in the same line, and are 

 slightly in advance of the maxillary notches. In the middle of the rostrum the 

 premaxillae are strongly convex and moderately high, while toward the distal end 

 they are higher and more nearly plane and vertical. 



The frontal plate of the maxillae is nearly flat, but is doubtless somewhat 

 distorted by pressure from above. The orbital and anteorbital borders of the 

 plates are very thin, as in Phocama. The anteorbital notches are broad and 

 shallow. Immediately in front of them the surface of the maxillae is horizontal 

 but more anteriorly it slopes gradually downward as in recent delphinoids. At 

 the middle of the rostrum the visible portion of each maxilla is about as broad 

 as one of the premaxillae. Behind the nares, the postero-internal borders of the 

 maxillae are separated by an interval of 30 mm., which is occupied by the frontals. 



The posterior border of the nasals is not clearly defined but they appear to be 



not represent the same species. 



belongs 



