FROM THE PHOSPHATE BEDS OP SOUTH CAROLINA. 221 



right one is the wider, and extends further backward and outward, though not so 

 far forward as the left one. The right tract is about six inches long and one and 

 three-fourths wide near its middle. 



In another fossil specimen from the same collection, and consisting of a frag- 

 ment of the right maxillary bone from a larger individual, the corresponding rug- 

 ged tract is eight inches long and nearly two inches wide. 



Back of the rugged tract, in the fossil under special examination, the surface 

 is extended in a broad crescentoid groove, outside the position of the prenarial 

 fossa, forming part of the supra-orbital fossa of the maxillaries. A, large foramen 

 just behind the rugged tract opens outwardly into a channel from the anterior 

 division of the infra- orbital canal. 



Laterally, the upper surface of the beak is defined posteriorly from the palatine 

 surface by a subacute ridge. This proceeds forward, and near the middle of the 

 beak divides into two branches which, continuing to advance with slight diverg- 

 ence, subside near the end. On the left side the principal ridge advances several 

 inches further than the right, and its branches are less conspicuous. In the fork 

 of the branches a neuro-vascular canal opens forward into a groove which gradu- 

 ally becomes obsolete in front. 



In the side view of the beak (fig. 1, PI. xxxi.) the median intermaxillary ridge 

 appears as its most elevated outline, but at the base the back end of the rough 

 tract of the maxillaries rises nearly to the same level. The lower outline forms a 

 moderate inflection between the end of the beak and the deep antero-posteriorly 

 convex carina intervening to the broad depressed surfaces for the palatines and 



pterygoids. 



Viewed beneath, the back of the beak exhibits a prominent carina with deep 

 sloping surfaces extending to the lateral subacute borders. The deep slopes pre- 

 sent broad, shallow, concave depressions for the palatine bones which are separated 

 from the lateral borders of the beak by narrower groove-like concavities. 



The median palatine carina is acute just in advance of the inferior nares, 

 becomes obtuse forward, and gradually expands on the transversely convex under- 

 surface of the anterior two-thirds of the beak. The acute portion of the carina 

 is continuous backward with the narial partition, and its sides are impressed by 

 the pterygoids. This portion of the carina appears to be formed by the vomer, 

 and is the only portion of that bone seen on the under part of the beak. 



The anterior two-thirds of the beak beneath form an elongated demi-cone not 

 exactly symmetrical on the two sides. No trace is visible of the original median 

 separation of the maxillaries. The palatine surface near the end of the beak pre- 



56 



