178 A NEW FOSSIL PORPOISE FROM MARYLAND. 



surrounded by a slender rod of bone. The diameter of the canal is about 14 mm. 

 The neural spine is very short. 



7th Cervical (PL XIX, fig. 13).— This vertebra has a long, slender and nearly 

 straight superior transverse process, directed outward and a little downward. 

 There is also a slender, curved inferior process about 11 mm. long directed 

 obliquely outward and downward. The neural spine is but little longer than 

 that of the 6th cervical; the neural canal elliptical. 



Thoracics. 



(PL XX, figs. 1-9; PL XXI, figs. 1-9; PL XXII, figs. 1-12.) 



Nine thoracic vertebrae are preserved, including what appear to be the 1st 

 and 3d. Five of them are nearly complete, and the remainder more or less 

 broken, or represented only by upper or lower portions. They differ noticeably 

 from the thoracics of many recent delphinoids and other odontocetes in that 

 the neural spines are nearly vertical, instead of being strongly inclined backward. 

 In this respect they resemble the vertebrae of Phoccena more closely than those of 

 any other recent genus with which I am acquainted. 



In the series of thoracics which has been preserved, the centra increase in 

 length rapidly from the first to the third, and less rapidly, but still perceptibly, 

 from that point backward. The metapophyses, from the 3d to the 7th thoracic, 

 are short, thick, and nearly horizontal, with the articular facets for the ribs 

 at first directed a little downward, but in the posterior vertebrae, outward. In 

 the 1st thoracic (PL XXII, fig. 1), the metapophysis is broad and thin, and the 

 articular facet for the first rib is directed obliquely downward. 



The last three vertebrae in the thoracic series are badly broken, but one of 

 them has the right transverse process intact. This is short, thick, and directed 

 outward, and is situated so that its long axis is in line with the top of the centrum. 

 It is not certain that these three vertebrae immediately follow the six preceding 

 them, and hence is impossible to determine whether the situation of the 

 articular facets for the ribs changes gradually from vertebra to vertebra as in 

 recent delphinoids, or whether it changes abruptly at about the 8th thoracic 

 from the side of the neural arch to the side of the centrum, as in Berardius and 

 other recent ziphioids. Apparently it changes gradually, as in Delphinus and 

 Tur stops. 



The neural spines, as already mentioned, are nearly vertical, and hence, 

 unlike those of many recent delphinoids. They resemble those of Phocana 

 among recent, and Eurhinodelphis among fossil forms. The spines of the more 

 anterior vertebrae are nearly straight, and somewhat tapering, but those farther 

 back are more or less recurved, especially at the tip. , 



The anterior zygapophyses are elliptical, nearly flat, and directed upwar . 

 The posterior zygapophyses are also elliptical and flat, and are directed down- 

 ward. 



The first six thoracics of the series at hand present facets on the postero- 





