PROFESSOR OWEN ON THE GENUS DINOENIS. 499 



ment of the ligamentum teres is as if a slice of the convexity had been cut off obliquely 

 from its most prominent part backward and a little upward, so that no part of this sur- 

 face appears in a direct front view ; and it is slightly, if at all, depressed : part of this 

 large flat surface had been broken away in the specimen figured (PI. LXXXIX. fig. 1). 

 In the few femora of the general size attributable to Bin. maximus there are varia- 

 tions in the relations of the cu'cumference of the shaft to the length of the bone, and in 

 one instance (the femur from Mr. Joseph) in the proportion of the breadth of the distal 

 end. In the instance (Mr. Joseph's) where this end of the bone is narrower, the back 

 part of the inner condyle is much narrower, and is more convex and more backwardly 

 produced. The form of the popliteal space also differs. In Plate LXXXIX., and the 

 majority of femora of Binornis, it is a deep oblong oval pit, definitely excavated, the 

 larger end toward the inner posterior tuberosity of the " linea aspera," and deepening to 

 the back ridge of the inner condyle, which extends toward the outer one. In the 

 femur from Mr. Joseph the depth of the popliteal pit is due to the backward projection 

 of the condyles and their uniting posterior ridge, dividing the popliteal from the in- 

 ferior intercondylar fossa, which is unusually deep. The modification of the distal end 

 of the less robust femur (from Mr. Joseph) is, indeed, such as to suggest a specific dif- 

 ference. The trochanter, also, rises more abraptly, is higher, and the outer ridge of tlie 

 antero-superior pit is unusually prominent. 



mia. (Plate XC.) 

 Of the tibia (PI. XC.) there need only to be given the dimensions, taken in accord- 

 ance with those which have been previously recorded of the Binornis giganteus and 

 other species '. All the characters of the bone which distinguish it generically as of 

 Binornis are closely repeated in the present specimen. 



Metatarsus. (Plate LXXXIX. figs. 3 & 4.) 

 The same remark applies to the metatarse (PI. LXXXIX. fig. 3) ; but between that 

 bone in Major Michael's series and the one in Dr. Lillie's there are diflferences of pro- 

 portion (probably within the limits of individual variety), which may be mainly appre- 

 ciated by comparison of the outline of the latter (fig. 4) added to the Plate (LXXXIX.) 

 which contains the finished lithograph of Major Michael's specimen (fig. 3). 



Dr. Lillie's specimen is longer and more slender, but with a greater transverse expan- 

 sion of the distal end. The back part of the middle articular trochlea at the distal end 

 pi-ojects more abruptly in Dr. Lillie's specimen ; but the generic characters of the meta- 

 tarsus of Binornis are closely maintained in both specimens. 



Subjoined are dimensions of the three chief bones of the hind limb of the present 

 enormous species [B. marimus), together with those of the same bones in Bijiornis 

 giganteus. 



' Trans. Zool. Soc. vol. iii. p. 246. 



