1050 
MR. J. W. HTJLKE ON THE OSTEOLOGY 
Iguanodon Mantelli, and in Birds. The ungual phalanges in shape resemble those of 
the pes, as it is now known they really do in Iguanodon Mantelli, the restoration of 
the manus of this dinosaur in the “ British fossil Reptilia ” being based on mistaken 
identifications. 
Hip-girdle and hind limb. 
Ilium (Plate 77).—This has the elongated form which characterises this bone in 
the Iguanodontidse. Its prseacetabular process, extremely long and slender, extends 
forwards upon the loins overhanging the posterior lumbar ribs. The acetabular arc 
ends anteriorly in a relatively slender pubic process directed downwards and forwards, 
and behind it is terminated by a low swelling which marks the attachment of the 
ischium. The lower border of the broad post-acetabular part, nearly straight, is 
slightly inflected, and is indented by a longitudinal groove. 
Ischium (Plate 75; Plate 76; Plate 77).—This bone was first identified by Professor 
Huxley in the British Museum fossil No. 39,460.* * * § It had before been considered to 
be a tibia, f It is the same bone which in Iguanodon Mantelli passed for so many 
years as clavicle.£ 
It has the form of a long slender bar directed backwards parallel with the lower 
border of the post-acetabular part of the Ilium. That this is its true direction may be 
seen by its impression in the stone below the left Ilium in the annexed sketch 
made several years ago of a fossil in Mr. Fox’s collection (Plate 77).§ The proximal 
end of the ischium is expanded. It has above a stout process, which united to a 
corresponding process on the Ilium behind the acetabulum, completed below and 
posterioly the circle of this articular hollow. This acetabular process is borne on a 
narrow part or neck, the axis of which makes an angle of about 90° with the long axis 
of the bone. Below the acetabular process and the neck is a wide rudely quadrilateral 
expansion directed downwards, the lower curved border of which contributes the lower 
margin of the acetabulum. Behind this expansion the bone rapidly contracts and con¬ 
tinues narrow through about half its length when it again widens. Nearly midway 
between its acetabular and its ventral or lower end is a lip-shaped out-turned 
obturator process (Plate 75, ob.p.), against which rests the rod-like part of the 
os pubis. The lower or ventral ends of the Ischia seem to be symphysially united. 
Pubis. —-The form of this bone repeats in miniature that of I. Mantelli (Plate 75; 
Plate 76, fig. 1; and Plate 77). It has a stout short part, or body, with a smooth 
articular surface, which in front is attached to the pubic process of the Ilium, and behind 
meeting the Ischium completes below and in front the circle of the acetabulum. From 
* Huxley, Quart. Journ. Geol Soc., vol. xxvi., plate i., fig. 3. 1870. 
f Owen, R., “ Fossil Reptilia of the Wealden Formation,” Pal. Soc., vol. for 1855, p. 2, t. 1. 
f Owen, R., £ Fossil Reptilia of the Cretaceous Formation,’ p. 105, plate xxxiv. 
§ This figure stows the right Ischium , which, has been uncovered since the above was written. 
