6o6 PELVIC GIRDLE. 



(469) H. Rathke. Uebcr die Entwicklung der Schildkrcten. Braunschweig, 

 1848. 



(470) H. Rathke. Ueber den Bait mid die Entwickhing des Brnstbeins der 

 Saurier, 1853. 



(471) A. Sab a tier. Comparaison des ceintures ct des membres anterieurs et pos- 

 ttrieurs d. la Strie d. Vertcbrcs. Montpellier, 1880. 



(472) Georg 'Swirski. Untersnch. iib. d. Entwick. d. Schultergiirtels u. d. 

 Skelets d. Brustflosse d. Hechts. Inaug. Diss. Dorpat, 1880. 



Pelvic girdle. 



Pisces. The pelvic girdle of Fishes is formed of a cartila- 

 ginous band, to the outer and posterior side of which the basal 

 element of the pelvic fin is usually articulated. This articulation 

 divides it into a dorsal iliac, and ventral pubic section. The iliac 

 section never articulates with the vertebral column. 



In Elasmobranchii the two girdles unite ventrally, but the 

 iliac section is only slightly developed. In Chimsera there is a 

 well developed iliac process, but the pubic parts of the girdle 

 are only united by connective tissue. 



In the cartilaginous Ganoids the pelvic girdle is hardly to be 

 separated from the skeleton of the fin. It is not united with its 

 fellow, and is represented by a plate with slightly developed 

 pubic and iliac processes. 



In the Dipnoi there is a simple median cartilage, articulated 

 with the limb, but not provided with an iliac process. In bony 

 Ganoids and Teleostei there is on each side a bone meeting its 

 fellow in the ventral line, which is usually held to be the rudi- 

 ment of the pelvic girdle ; while Davidoff attempts to shew that 

 it is the basal element of the fin, and that, except in Polypterus, 

 a true pelvic girdle is absent in these types. 



From my own observations I find that the mode of develop- 

 ment of the pelvic girdle in Scyllium is very similar to that of 

 the pectoral girdle. There is a bar on each side, continuous on 

 its posterior border with the basal element of the fin (figs. 345 

 and 347). This bar meets and unites with its fellow ventrally 

 before becoming converted into true cartilage, and though the 

 iliac process (il) is never very considerable, yet it is better deve- 

 loped in the embryo than in the adult, and is at first directed 

 nearly horizontally forwards. 



Amphibia and Amniota. The primitive cartilaginous pelvic 



