554 GEOLOGICAL SURVEY OF THE TERRITORIES 



SYNOPLOTHERIUM. Cope. 

 Proceedings Amerijcan Philosopliical Society, 1872, 483, (publisbod August 20.) 



Represented as yet by a single species, which is known from frag- 

 mentary remains of a single individual. The portions preserved are : 

 a large part of the skull with nearly complete dentition, the superior 

 molars loose ; lumbar and caudal vertebne ; large portions of both fore 

 limbs, including the bones of the feet; smaller portions of the hind 

 limbs and feet. 



The bones of the /on? limbs are stout in their proportions. The 

 humerus has a well-marked rugose line for muscular insertion on its 

 posterior face, but no prominent angle. Distally the inner and outer 

 condylar tuberosities are almost wanting, and there is neither external 

 aliform ridge, nor interiuil arterial foran)en. The olecrauar and coro- 

 noid fossic are conlluent, forming a very large supracondylar foramen. 

 The condyles are moderately constricted medially, and there is a well- 

 marked submedian rib separated from the outer condyle by a constric- 

 tion. The latter is continued as an acute ridge on the outer side of the 

 olecranar fossa. The inner condyle is the more j)rominent, and its outer 

 margin is a sharp, elevated crest. The ithia has a very prominent su- 

 perior process, continning the cotylus upward. The coronoid process, on 

 the other hand, is rather low. The radial cotylus is fiat and broad. 

 The distal end is not preserved. The radim has a more transverse head 

 than Canis or Felis^ and has three articular planes, the inner being a 

 wide, oblique truncation of the edge. The shaft is angulate below, and 

 becomes a litttle deeper than wide near the distal end. The extremity 

 is lost. The cmyal bones are probably all present. The fore foot was 

 found in place so that the relations of the bones are know^u with cer- 

 tainty. The scaphoid and lunar appear to be distinct. The former 

 exhibits proximally the inner tuberosity, then a slight concavity, and 

 then the convexity, where it is obliquely truncated so as to give a gen- 

 eral rhomboid outline. Beneath there are but two facets, the inner the 

 deepest, and divided lengthwise by the truncation of the bone. The 

 larger facet fits correctly the 0. 0. trapezium and trapezoides. The lunar 

 was not found in its place, but two fragments taken from the matrix 

 just behind it, adhering to the pisiforme probably belong to it. The 

 upper face is concave. The cuneiform is large and concave lengthwise 

 aljove for the narrow extremity of the ulna. Below it has alarge concave 

 facet for the unciform. The pisiforme is of unusual size, and is as stout 

 as the largest metacarpus, and neavly half as long as the outer (5th) 

 metacarpal. It articulates with a thick V-shaped facet of the cuneiform. 

 Its extremity is obtuse and expanded. The trapezium is large and at- 

 tached to its metacarpus laterally, sending a process downwards 

 posteriorly. If supports a narrow articular surface for the metacarpus 

 of a small pollex or inner digit, which is not preserved. The trapezoid 

 is smaller and of a triangular outline, with the base forwards. The 

 magnum is a rather small bone articulating as usual with the metatar- 

 sals 2 and 3. It is depressed in front. The unciform is a large bone 

 with a considerable external anterior ^surface. Two-thirds of its upper 

 surface are in contact with the cuneiform, the remaining part projecting 

 upwards with convex face to unite with the lunare. Below it supports 

 metatarsals 4 and 5. 



There were probably five digits of the fore foot, the inner small or 

 rudimental. The proportions are stouter than in the dogs, but not so 

 much so as in the bears. The j>/<fl/««^a' have a length hiaiilar to that 



