PLATE 48. 



RHINOPTERIDAE. 



Fig. 1-3. Rhinoptera jussieui (Page 447). Fig. 4. Rhi.\opter.\ m.\rginata (Page 445). 

 Fig. 5-6. Rhinoptera lalandii (Page 445). 



1. Teeth from a very young speeinien. M. C. Z. .311. 



2. Teeth from a larger specimen. M. C. Z. 316. "^ 



3. Teeth from a large specimen. M. C. Z. 535. 



4. Jaws and primary dentition. M. C. Z. 631. 



5. Teeth from a medium sized specimen. M. C. Z. 534. 



6. Teeth from a large .specimen. M. C. Z. 534. 



Figures 1, 2, and 4 illustrate the changes in dentition during the period of rapid growth from very 

 young stages. The small round primary teeth in front of the pavements suggest derivation from an- 

 cestral forms with dentition resemhling that of some Dasybatidae. In fig. 3 and G are shown the teeth 

 of large specimens. Figures 3 and 5 show dentition that have been much affected by individual variation. 



