392 



ZOOLOGY 



metacarpal bears two phalanges, the proximal one {ph.^') produced 

 postaxially into a flange, the distal one {ph.^") pointed ; the third 



metacarpal bears a single pointed 

 phalanx {ph. 3). 



Th.e pelvic girdle (Fig. 1027) resembles 

 that of no other Vertebrate with the 

 exception of some Dinosaurs. The 

 ilium (il.) is an immense bone attached 

 by fibrous union to the whole of the 

 synsacrum aud becoming ankylosed with 

 it in the adult. It is divisible into pre- 

 acetabular and p}Ost-aceta'bular portions of 

 approximately equal size. As usual it 

 furnishes the dorsal portion of the 

 acetabulum, and on the posterior edge 

 of that cavity is produced into a process, 

 the antitrochanter (a.ir.), which works 

 against the trochanter, a process of the 

 femur. The ventral portion of the 

 acetabulum is furnished in about equal 

 proportions by the pubis and ischium 

 (Fig. 103(3) : it is not completely closed 

 by bone, but is perforated by an aperture 

 covered by membrane in the recent 

 state. Both pubis and ischium are 

 directed sharply backwards from their dorsal or acetabular ends. The 

 ischium (is.) is a broad bone, ankylosed posteriorly with the ilium, 

 and separated from it in front by an ischiadic foramen (Fig. 1027, 

 is. for. ;Fig. 1036, i.s.f). The jjmWs (pu.) is a slender, curved rod, 

 parallel with the ventral 

 edge of the ischium, and 

 separated from it by an 

 ohiurator notch (Fig. 

 1027, olt.n. ; Fig. 1036, 

 oh.f.). Neither ischium 

 nor pubis unites ven- 

 trally with its fellow to 

 form a symphysis. 



In the hind-limb the 

 /mw (Fig. 1037, /e.) is 

 a comparatively short 

 bone. Its proximal ex- 

 tremity bears a pro- 

 minent trochanter (tr.) 



and a rounded head (hd.), the axis of which is at right 

 angles to the shaft of the bone ; so that the femur, and 

 indeed the whole limb, lies in a plane parallel with the 



Fio. 103j.— Columbalivia. Lo't 

 manus of a nestling. Tho car- 

 _ tilaginoua parts ■ are dotted. 

 rp. 1, radiale ; cy>. ii^ ulnare ; 

 mcp.l,S,3, metacarpals; ph. 1, 

 phalanx of first digit ; ph. 2, 

 ph. 2',-plialanges of second digit ; 

 ph. 3, phalanx of third digit ; 

 ra. radius ; ul. ulna. (From 

 Parker's Zootomy/.) 



Fig. 103U.— Columbalivia. Left innominate of a nest- 

 ling. The cartilage is dotted, ac. acetabulum ; a. tr. 

 anti-trochanter ; i[. pre-acetabular, and W. post-aceta- 

 bular portion of ilium ; is. ischium ; i. s. f. ischiadic 

 foramen ; ob.f. obturator notch ; jJW. pubis. (From 

 I'arker's Zootot'iiy.) 



