SHARK GENUS ISURUS — GARRICK 



677 



any significant difference from those of the long-finned species but 

 are given below for comparison: 



Isurus oxyrinchus number of vertebrae 



Centra very regular along entire vertebral column. Centrum diam- 

 eter much greater than centrum length even in longest mono- 

 spondylous centra at posterior region of abdomen. Diplospondyly 

 occurs over anterior thii-d to middle of pelvic base. 



T^. — : — of penultimate monospondylous centrum=0.46 to 0.55. 

 Diameter f ^ 



Length of penultimate monospondylous centrimi _ 



Length of fii'st diplospondylous centrum 



Isurus alatus, new species * 



Long-finned Make 



Isurus glaucus. — Strasburg (in part), 1958, p. 357. [Central Pacific] 

 Isurus oxyrhynchus. — Fourmanoir (in part), 1961, p. 79. [Madagascar.] 



Study Material. — Holotype: U.S. Nat. Mus. no. 197427, male, 

 1,233 mm., from the tropical Indian or Pacific Oceans, collected during 

 1962 by a Japanese long-Hner, and supplied by T. Abe. 



Paratypes: U.S. Nat. Mus. no. 197429, female, 1,372 mm., same 

 data as holotype; U.S. Nat. Mus. no. 197435, mature male, incomplete, 

 lacking caudal fin and first dorsal fin, 1,720 mm. long from snout tip 

 to just in front of precaudal pits, same data as holotype. 



Supplementary Material. — U.S. Nat. Mus. no. 196024, jaws, 

 skin sample, photographs and measm^ements of male, 1,251 mm., 

 from equatorial Pacific between 150° W. and 170° W., May 3, 1953, 

 USFWS, Pacific Oceanic Fishery Investigations (MV John R. Man- 

 ning, Cruise 15, Station 2); U.S. Nat. Mus. no. 196039, jaws, photo- 

 graphs, and measurements of male, 1,801 mm., from equatorial 



^Precaudal centra include all complete centra anterior to a vertical through 

 the forward margin of the upper precaudal pit. 



8 As mentioned in footnote 3, Guitart Manday (1966) has recently described 

 this species under the name /. paucus, which, therefore, has priority. 



