Dr. A. Smith Woodrcard — On Dinodocus Mackesoni. 205 



agreed that it was truly a Sauropoclous Dinosaur, thougti of uncertain 

 affinity. 



The remains of Ditiodocus are very fragmentary, and Owen records 

 that owing to the difficulty of extricating them from the matrix they 

 were '' less characteristic " when they reached the British Museum 

 "than when [he] took the description and sketches of them on the 

 spot where they were found." The puhlished description, in fact, 

 gives no clear idea of the nature of the bones, and they can only be 

 interpreted by discoveries which have been, made since it was written. 



The task of determining all the bone- 

 fragments would be more laborious than 

 profitable, but a careful study of the col- 

 lection has proved that some of them can 

 be united into two important elements, 

 the humerus and the ulna, which are 

 specially worthy of notice. These are 

 now mounted for exhibition in the British 

 Museum, and the humerus is represented 

 in the accompanying text-figure. 



The upper half of the left humerus is 

 shown in Owen's pi. xii, fig. 6, and 

 described as a "fractured portion of the 

 ilium." The bone itself is in small pieces, 

 but there is a perfect mould of its anterior 

 face in the hard Greensand matrix, so that 

 at least this aspect can be completed in 

 plaster. The lower half of a humerus is 

 described and figured by Owen (loc. cit., 

 p. 48, pi. xii, fig. 1) as "lower end of 

 shaft of femur"; but its surface is so 

 much fractured and the distal end is so 

 incomplete that it is not easy to determine 

 whether the specimen belongs to the right 

 or to the left side. On the whole, I am 

 inclined to refer the bone to the right side, 

 and have reversed the drawing of it in 

 the accompanying figure. The two halves 

 do not quite meet in the middle, the lower 

 fractured end having been ground to 

 display the nature of its cross-section. As 

 remarked by Owen, the bone is solid, but 

 the cancellous interior is of so open a 

 texture that it might readily disappear 

 in a fossil. The extreme length of the 

 humerus must have been originally about 

 1'25 m., the width of its upper end 40 cm., 

 and the width of its lower end not less 

 than 30 cm 



Anterior aspect of left humerus 

 of Dinodocus Mackesoni, Owen, 

 from the Lower Greensand, near 

 Hythe, Kent ; iV nat. size. 

 [Brit. Mus. No. 14695.] 



Its upper end is deeply concave on its anterior face, 



the deltoid crest being specially prominent. The shaft is slender, and 

 the lower end, which lacks a few centimetres in the fossil, shows the 

 usual prominence on the anterior face above the outer condyle. 



