672 PROCEEDINGS OF THE NATIONAL MUSEUM vol. iis 



recognized by these authors are largely dependent on specimen size. 

 Thus only juveniles clearly fit the criteria of I. glaucus, while middle- 

 sized specimens show more affinity with /. oxyrinchus, and large spec- 

 imens usually agree with I. tigris. In the case of /. glaucus and /. 

 tigris these size characterizations follow from the sizes of the types; 

 the types of /. glaucus were juveniles, the largest being 1,020 mm. long 

 (selected by Boeseman (1947, p. 217) as lectotype), and the type of /. 

 tigris was a large adult, 2,690 mm. long. Isurus oxyrinchus has been 

 interpreted in recent years mostly from the excellent account and 

 illustrations of a specimen 1,640 mm. long in Bigelow and Schroeder 

 (1948, p. 125, fig. 18). Application of Bigelow and Schroeder's and 

 of Smith's criteria for the species does not produce clear-cut results 

 when a series of specimens is examined. This of course would be 

 expected in view of the evidence given here on the size-dependency 

 of the criteria and on the variation which occurs. Thus Cadenat 

 (1962, p. 309) reports that foiu* West African specimens which he has 

 examined show more affinity with /. tigris as recognized by Smith, 

 but in some characters, differing from specimen to specimen, there is 

 agreement with /. oxyrinchus. I have found similar overlap in New 

 Zealand specimens which, if small, could be variously identified as 

 /. glaucus or /. oxyrinchus depending on the character used, or if large 

 could be 7. oxyrinchus or I. tigris. Dr. F. Talbot informs me (per- 

 sonal communication) that a series of makos caught off Capetown 

 offered the same problems. 



Examination of the features which were thought distinctive for 

 the nominal species of makos when first described does not provide 

 any other evidence for recognizing more than one species of short- 

 finned mako. Rafinesque (1810b, p. 60) distinguished his Mediter- 

 ranean 7. spallanzani from the Mediterranean I. oxyrinchus on the 

 grounds that 7. spallanzani lacked a lateral line. However, all makos 

 have lateral lines. Lesson (1830, p. 93) did not diagnose his Atlantic 

 i. cepedii and made no comparison with other makos. Miiller and 

 Henle (1841, p. 69) differentiated the Pacific 7. glaucus from 7. 

 gomphodon (locality unknown) on the position and shape of the first 

 dorsal fin — features already treated here. Gill (1862b, p. 409) named 

 the Atlantic 7. dekayi on De Kay's (1842, p. 352) account of Lamna 

 punctata, but in neither account is there any discussion of the diag- 

 nostic characters. Atwood (1869, p. 268) compared his Atlantic 

 1. tigris only with Carcharias atwoodi Storer which is now known to be 

 a synonym of Carcharodon carcharias. Murray (1884, p. 349) differ- 

 entiated his Indian Ocean 1. guentheri from 7. glauca and /. spallanzani 

 (and from Lamna cornubica) on the basis of its greater number of 

 teeth, the position and shape of the fins, the length of the caudal 

 keel, and the presence of a prominent lateral line. The question of 



