Cope.] 532 [iTov. 18, 



Saukocephalus prognathus. Cope sp. nov. 



This si:tecies is represented by a premaxillary and attached proximal 

 portion of the maxillary bones of the right side, and by a large number 

 of vertebrse and other bones. These portions were associated in the 

 collections placed in my hands by Prof. Mudge, and relate to each other 

 in size, as do those of the preceding species and the Iclithyodecies 

 ctenodon. 



The premaxillary is characterized by its great depth as compared with 

 its length, and by the shortness of its union with the maxillary. The 

 palatine condyle of the maxillary reaches a point above the middle of the 

 alveolar margin of the premaxillary. The latter contains alveolae of seven 

 teeth, the anterior of which only presents a perfect crown. This is still 

 more elongate than the crown of the teeth of 8. pJilebotomus. It is com- 

 pressed, equilateral, smooth, and acute. Its direction is even more ob- 

 liquely forward than the anterior outline of the bone, which itself makes 

 an angle of 50° with the alveolar border. 



The vertebrse consist of cervicals, dorsals, and caudals, to the number 

 of about sixty, most of which are supposed to have been derived from the 

 same animal. The groves are as in 3. plilebotomus, there being two be- 

 low, two on each side, and two above. The latter receives the bases of 

 the neurapophyses, which are in many cases preserved. The inferior 

 pair of grooves becomes more widely separated as we approach the cervical 

 series, leaving an inferior plane, which is longitudinally striate grooved. 

 This plane widens till the grooves bounding it disappear. The inferior 

 lateral groove becomes widened into a pit which some of the. specimens 

 show to have been occupied by a plug-like parapophysis, as in Elops, etc., 

 or a rib-head of similar form. The neurapophysial articular grooves be- 

 come pits anteriorly, and these only of all the grooves, remain on the ante- 

 rior two vertebra in the collection. Some of the posterior caudals preserve 

 large portions of the neural arches and spines. They form an oblique 

 zigzag suture with the body, consisting of two right angles, one project- 

 ing upward anteriorly another downward behind. The neural spines are 

 very wide and massive and in close contact antero-posteriorly ; these 

 probably support the caudal fin. They are deeply and elegantly grooved 

 from the basis upwards. The centra exhibit no lateral grooves. 



An unsymmetrical fin ray accompanied these remains, and from its 

 mineralization, color, size, and sculpture, probably belongs to them. The 

 anterior margin is thinned, and with obtuse denticulations, the posterior 

 truncate. The section is lenticular, with a deep rabbet on one side of the 

 posterior edge ; section at the base, apex circular lost. The sculpture 

 consists of fine longitudinal raised striae, which bifurcate and send 

 numerous similar ridges to the teeth of the anterior margin. It is pro- 

 bably a spine of a pectoral fin. It is identical in form and sculpture with 

 that recently described by Leidy as Xiphactinus audax, but differs in 

 specific details. 



