l62 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 52 



MOBULID.^ 



The jMobnlids or Devil-fishes inckide the largest as well as the 

 widest of rays. Behind the anus the tail is abruptly attenuated and 

 developed as a whip-like appendage without efficient spines. The 

 mouth, instead of being inferior, as in other types, is in front, and 

 the jaws have weak teeth or are partially toothless. The pectoral 

 fins are extended outward in a w'ing-like manner, and long, flexible, 

 horn-like processes or fins are developed on each side of the head 

 and bound a preoral space. These processes (caropteres, head-fins, 

 or horns) can be used for grasping, and a number of cases have been 



Fig. 51. — Tail of the Devil-lish. After Holmes. (Proceedings Elliott Society 

 of Natural History, I, pi. 3.) About half natural size. i. Knob and 

 base of tail. 2. Bone with the small spine as extracted from the 

 knob. 3. Upper view of the same with the posterior spinelet (in 

 white). 



recorded of a Devil-fish seizing the anchor of a vessel and running 

 away with both anchor and vessel for some distance, to the wonder 

 and fear of the sailors. The spines about the base of the whip-like 

 tail, characteristic of the nearest relations of the Devil-fishes, the 

 Sting-rays and Eagle-rays, are reduced in size and sometimes to a 

 minimum in the Devil-fishes. In the typical species the spine is 

 quite rudimentary and concealed in a subosscous swelling at the base 

 of the tail behind the small dorsal fin. 



Further, the Devil-fishes are peculiar in the possession of pre- 

 branchial organs, to be noticed later. 



