I 5 8 



S EL A CHI 1 



TRIBE 2. 



The pectoral fins fuse in front with the sides of the head, and 

 the branchial openings are quite ventral. The rostrum, as a 



FIG. 121. 



Skeleton of Raja Imtis, L. (From Owen, Anat. of Vertebrates, by permission of Mesh, 

 jnans and Co.) 7, scapular region of pectoral girdle; S, 9, 10, segments of anterior axis of 

 pectoral lin ; 11, posterior axis ; 12, radials of expanded pectoral tin; 19, preorbital process ; 

 52, cartilage plate joining scapula to vertebral column ; 5">, posterior outgrowth of pectoral 

 girdle; 63, pelvic girdle ; 68, basipterygium ; c, anterior enlarged radial ; r, pelvic-tin radials. 



rule, is much developed. In this division most of the changes in 

 the skeleton described above (p. 154) are carried out. Extra* 

 branchials are preserved in the Rhinobatidae and in Trygon. The 

 iliac process may be much developed ; since it is large in the 

 Holocephali and in the Tetrapoda, this is possibly a primitive 

 character. 



