OF GALLINACEOUS BIRDS AND TINAMOUS. 225 



that of the latter, but there is no coalescence (in this specimen) with the side of the 

 sacrum. The prefemoral part of the ilium is flat in front and gently scooped behind ; 

 the hinder part of the bone is gently convex, has a slightly arcuate external outline, 

 and is truncated obliquely behind, the internal angle going furthest back. The bone 

 is very thick at its outer edge, behind the acetabulum, looking precisely as if it had 

 been evenly pared away by a knife (PI. XXXIX. il. isc.) ; the thick edge is quite flat. 

 Morphologically, a large piece has been cut away — all that somewhat incurved plate of 

 bone which should reach to, and coalesce with, the posterior two-thirds of the upper 

 edge of the ischium : here we have not the enclosed ischiadic foramen of the ordinary 

 bird, but the great gaping " ischiadic notch " of the Cassowary, Apteryx, and Emu. In 

 the African Ostrich this cleft is enormous ; but the ischium unites with the pubis, and 

 the pubis with its fellow of the opposite side. In the Rhea a broad band of tendon 

 ossifies and binds the stunted hinder part of the ilium to the ischium below ; and the 

 same bond exists between the ischium and pubis : the latter is a very rare condition, 

 yet it is seen also in the Hornbills (Buceros). 



Notwithstanding this curious anticipation in the Rhea of the Hornbill's pelvis, the 

 ilium of the former bird is not better developed behind (this postfemoral part is an 

 ornithic stronghold) than in the Apteryx. The ischium and pubis of the Tinamou 

 (PI. XXXIX., isc. ph.) are very little removed from those of the Apterijx, and in both 

 the Tinamou and the Apteryx the preacetabular projection of the bone (PI. XLI. fig. 3, ac.) 

 at the junction of the pubis with the ischium is as strongly developed as in the 

 Fowl. The acetabulum is only half the size of that of the Common Cock, and is not so 

 neatly scooped ; it is equally imperfect internally. That which gives a certain gallina- 

 ceous character to the ischium and pubis is, that they are elegantly bowed, first out. 

 wards and then inwards (Pis. XXXIX. & XLI. fig. 3) ; the space between the bones, 

 however, is large, and this long obturator notch is partially divided into two by the 

 descending process near the head of the ischium ; behind this process there is another 

 notch (PI. XXXIX. isc), as in the Apteryx. In the Fowl the gap in front of the 

 notch becomes developed into a true obturator foramen, whilst the descending process 

 of the ischium is more than seven lines in extent, and anchyloses with the pubis. In 

 the Syrrhaptes and Hemipodius this whole tract keeps open ; and in Lagopus the pubis 

 adheres closely to the ischium, but for a long while keeps distinct. 



Subjoined are a few measurements of the sternal apparatus of a Common Fowl of 



medium size, in which the whole length of the sternum equalled that of the Tinamou ; 



and of the same parts in the latter bird. 



inches, lines. 



Length of scapula {xramou .' 2 7 



fFowl . . 34 

 Greatest width of scapula 1 Tinamou . 3i 



2 g2 



