228 PEOr. W. K. PAEKEE ON THE 



Dec. 15th, 1887. I bad found the bony continuity of this spur with the ilium in the 

 Chick long ago, and DoUo, in his invaluable paper on lyuanodon bernissartensis (Bull. 

 Mus. Roy. Hist. Nat. Belg. t. ii. pi. iii. fig. 4, c), shows the same thing. Mr. Hulke, 

 referring to a sketch by me of this part in the Chick, says : — ■" You represent the pre- 

 pubic spur as wholly iliac. The corresponding spur in Apteryx and Rhea americana 

 certainly contains a pubic element, for a suture in immature specimens runs through 

 the spur, which thus has an iliac and a pubic component." 



In the 2nd stage (Plate XXV. fig. 4) the carinate type of hip-plate is almost reached, 

 but the post-ilium and the ischium are still distinct. For the sake of comparison with 

 the hip-girdle in another family, the Hemipodidse (Turnicidoe), I have shown the 

 ossifying pelvis in one of the smallest of the typical Fowls, namely, the Quail ( Coturnix 

 communis) (Plate XXV. figs. 4 & 5). All the osseous centres are present in the recently- 

 hatched Quail (fig. 4, pr.i., ])t.i., pb., isc.) ; the ilium has used up all the cartilage in front ; 

 but its post-iliac extension still leaves a soft selvedge behind ; the same is seen in the 

 pubis and ischium. In both these figures, in this stage, the pubis is hooked upwards and 

 inwards, the hook being wedged in between the ilium and ischium, below the acetabular 

 fenestra. The synchondroses are still large, and the prepubic spur {pr.p.) is not 

 yet hardened. Afterwards, in a Fowl of the 1st summer (4 or 5 months old), the 

 ischium, being a stronger ossification, has grown over and hidden the pubic wedge, and 

 thus the ischium meets the ilium, not only behind, but also below the acetabulum 

 (fig. 12). This domination of the larger over the lesser parts can be seen in both the 

 cartilaginous and osseous stages of growth, and has to be allowed for in the determina- 

 tion of homologous parts ; a strong element is very apt to " suck the verdure out " of 

 one that is feeble. 



The limb is, for convenience' sake, generally studied as something distinct from the 

 limb-gu'dle ; it is, however, only the mobile part of the limb, the girdle being the fixed 

 part, the swinging- point, or " pier." For this additional part of the body of a vertebrate 

 animal is but a sort of " delamination " of the inner, or endoskeletal, layer of the 

 somatopleure, which, forming outside the ribs, works itseK outwards to become a free 

 limb-bud, then a flipper or fin, and lastly a paw, a hand, or a foot. This part in a liigh 

 vertebrate has, as a rule, a broad jn'oximal part, a narrower waist, and a dilated and 

 radiating distal tract ; the narrow waist becomes the humerus or the femur, which 

 is the isthmus or the connecting-link between the limb-girdle and the limb. No special 

 morphological names have yet been given to the part above the waist : the old human- 

 anatomy terms cling to the upper elements, and still serve in some degree for the lower. 

 For these, however, even some of the individual elements have had, very profitably, a 

 new and accurate morphological name given to them ; but the regions, also formed 

 by the transverse segmentation of the skeleton of the limb, have also received a special 

 nomenclature. 



Dr. O. C. Marsh, in a paper " On the Limbs of Sauranodon" which is to one seeking 

 to interpret the limbs a " golden key " (Amer. Journ. of Sci. vol. xix. Feb. 1880, pp. 169- 

 171, fig- 1), suggests the following terms for the regions of the higher kind of hmb 

 (cheiropterygium) (p. 170) : — 



