288 Papers from the Marine Biological Laboratory at Tortugas. 



Agassiz records four species of fossil Aetobatis which he had studied, of 

 which he figures only two. Text-figures lo and 1 1 are dorsal and lateral views 



respectively of the lower jaw 

 of Aetobatis sulcatiis with ten 

 teeth, the original of which is 

 preserved in the Museum of 

 Paris without indication of its 

 origin. 



Miiller and Henle (1841), un- 

 der the heading genus Aeto- 

 batis, say: 



The under jaw projects beyond 

 the upper jaw, which has a straight 

 edge. The tooth plates form in each 

 jaw a single row, without lateral 

 teeth, and are in the under jaw bent 

 parallel to the edges of the same. 

 The tooth-plates do not take up 

 the whole width of the jaws. 



ID, Lower jaw. ii, Lateral view 



of same. 

 Text-figs, id and ii. Jaws of Aetohatus sulcatus 

 (fossil). After Agassiz. 



Among the characters for A . narinari are : 



The edge of the under jaw and the margins of its pavement teeth present a flat curve 

 which forms in the middle a blunt angle. 



Cuvier, in the Atlas to the volume "Pois- 

 sons " of "Le Regne Animal" (1836-49) on plate 

 118, figure 4a, gives a figure (text-fig. 12) of a 

 lower jaw of which the description reads " Dents 

 de la Myliobate narinari.'' In the text, however, 

 nothing could be found. The rounded outline 

 of these teeth, as compared with the angled 

 structure of Key West and Beaufort specimens, 

 is very noticeable. 



The celebrated anatomist, Richard Owen 



(1840-45), in his "Odontography," copies both 



figures and descriptions (including the error) of 



Aetobatis narinari from Agassiz. This error was 



for Agassiz merely typographical, of course, and Text-fig. 12. Lower jaw of 

 ,1 , . J ^1 ^ . u J. Myliobatis tiarinari, after 



IS, as has been shown, corrected m the text, but Cuvier. 



the same excuse can not be advanced for Owen. 



Owen comments upon the absence of the lateral teeth found in the Mylio- 

 batids (by which he means Aetobatids of Miiller and Henle), upon the 

 strength of the jaws which support and work such heavy teeth, approach- 

 ing as they do close to the solidity of bone. However, Owen figures a 

 section through the head of a dried A. narinari, showing the projecting 

 lower jaw, calls attention to it, and remarks that it can be used in digging 

 shellfish out of sandy bottoms for food. This figure is so small and the 



