Thccodontosaurus and Palicosaurus. 159 



humerus. It has lost both proximal and distal ends, but has 

 the radial crest preserved, showinj^ a type in which the 

 proximal end of the bone was greatly expanded relatively to 

 the distal end ; and this type conforms to the Saurischian 

 plan. It is very well n-presented by the humerus 118, wliich 

 is similarly imperfect distally and h;is lost the radial crest, but 

 preserves the articuhir liead. The rii^ht humerus no. 37 also 

 has the articular head and radial crest imperfect, but preserves 

 the distal end of the bone. These specimens appear to be 

 referable to more than one species; but the plan of the bone 

 is the same in them all, so that an idea of the form of the 

 humerus in Palao^aurus may be gathered from them. 



Fio:. 8. 



Radi&l creat. 



Pi'oximul nrticulation. 



Di-tal fracture. 



Inferior n.^pect of a rip^ht humerus of Palcposaunis, showing the proximal 

 articulation ; imperfect distally. Brist. Mus. no. 118. 4 nat. size. 



The transverse width of no. 66 at the base of the radial 

 crest is 3i inches ; but since the head of the bone is broken 

 away, the transverse measurement was probably not less than 

 4 inches. The shaft is | inch thick, and the compressed 

 tuberosity of the radial crest is l-j^y ii^ch long. The large 

 radial crest extends for a considerable distance down the 

 length of the shaft, and the length of the bone, of which 

 indications are preserved, amounted to 7 inches, without 

 evidence of the extremity of either proximal or distal end. 



No. 118 is a smaller bone (fig. 8), with a transverse width 

 of the shaft of about yV inch, whicii is similar in size to no. 37. 

 The complete proximal outline of tiie articular head is convex. 

 The head is directed inward at an angle of 45° to the length of 

 the shaft, and appears also to be twisted at an angle of 45° to 



