674 PROCEEDINGS OF THE NATIONAL MUSEUM vol. us 



margin of its cusp — it agrees therefore with short^finned makos in this 

 respect and not with the long-finned species described as new here. 

 Cadenat regarded as improbable the likelihood that his mako is abnor- 

 mal, on the groimds that the abnormality would not be bilaterally sym- 

 metrical. Evaluation of the status of the specimen must await further 

 material. 



Cadenat also pointed out that of the Isurus material that he has ex- 

 amined, the jaws of 12 specimens from Madeira, Senegal, and the 

 Ivory Coast in the collection of I'lnstitut Frangais d'Afrique Noire at 

 Goree, Senegal, are very consistent in having a dental formula of 



— — . Jaws which Cadenat has seen from other localities show 



xo xo 



more or less variation, and Pacific specimens generally tend to have 

 fewer lower teeth. The tabulation below gives frequency distributions 

 for the number of lower teeth in Isurus specimens from the Pacific, 

 Atlantic-Mediterranean, and Indian Oceans, using Cadenat's data plus 

 my own. This tabulation tends to confirm Cadenat's view that Pa- 

 cific specimens have fewer lower teeth, though a more adequate sample 

 of Pacific material is needed to substantiate the view. 



Counts of teeth in one-half of the lower jaw of Isurus oxyrinchus 

 are as follows: 



On the basis of the above discussion, I regard as conspecific all 

 short-finned makos presently reported, viz, the 12 nominal species 

 listed on page 665; they take the name Isurus oxyrinchus Rafinesque, 

 1810. 



Isurus Rafinesque, 1810 



/swrws Rafinesque, 1810a, p. 11. [Type species /surMS oxyrinchus Rafinesque, 

 1810a, by monotypy.] 



For generic synonymy, see Bigelow and Schroeder (1948, p. 123). 



Isurus oxyrinchus Rafinesque, 1810 

 Short -finned Mako 



Isurus oxyrinchus Rafinesque, 1810a, p. 12, pi. 13. [Sicily.] 



Isurus spallanzani Rafinesque, 1810b, p. 45. [Sicily.] 



Squalus (Lamna) cepedii Lesson, 1830, p. 93. [Tropical Atlantic] 



Oxyrhina gomphodon Miiller and Henle, 1841, p. 68, pi. 28. [Oceanic] 



