PLATE 51. 



CARCHARIDAE. 



Fig. 1-6. Sc.\PANORHYNCHUs owsTONi. M. C. Z. 1048 (Page 28). Fig. 7. Carcharias taurus. 

 M.C. Z. 210(Page25). 



1. Skull in longitudinal section. 



2. Branchial skeleton from below. 



3. Branchial skeleton from above. 



4. Pelvis and radials. 



5. Heart, conus, and arteries. 



6. Intestine with spiral folds. 



7. Intestine. 



In most features the structure of Scapanorhynchus is closely allied to that of Carcharias. This is 

 very evident in the parts of the anatomy given on this plate but not previously figured. At first sight 

 the snout appears to present most divergence but most of this disappears on closer comparison of the 

 long snout with the short one. The large cartilage in fig. 3 behind the copula, glossohyal, between it and 

 the first ceratobranchial, is the first hypobranchial; it is present also in Carcharias, see Fiirbringer, 

 1903, Morph. jahrb., 31, pi. 17, f. 20 x. Three extrabranchials are shown in fig. 2 of Plate 51, a slender 

 rudiment of a fourth was present. As in most other items, the intestines of these genera, fig. 6, 7, have 

 much in common. 



