Fishes of the Western North Atlantic 433 



Anal about i.i to 1.3 times as long at base as 2nd dorsal, generally similar in shape, deeply 

 incised near the apex much as in diplana and in zygaena. Distance from origin of anal to tips 

 of pelvics between % and % as long as base of anal. Pelvics only about % as long at base 

 as anal, their anterior margins more strongly convex and the posterior margins more 

 deeply concave than in any other Atlantic member of the genus. Pectoral noticeably small, 

 its length a little more than Y2 as great as that of head in young but nearly % (72 to 73%) 

 that length in adults or about as long as vertical height of ist dorsal, a little more than Y> 

 as broad as long, its outer margin strongly convex toward apex in young but less so in 

 adult, its distal margin only moderately concave, apex subacute and inner corner narrowly 

 rounded. 



Color. Small specimens are brownish gray above and a paler shade of the same tint 

 below; the dorsals, lower and upper caudal lobes, upper surfaces of the pectorals and 

 lower edge of the caudal are dusky toward the tips. A cast of a large one, colored from the 

 fresh-caught specimen, is dark olive above and pale olive below, without any conspicuous 

 fin markings. 



Size. Available information suggests a length slightly less than 700 mm. at birth 

 which corresponds to the large number in a litter. This is the largest of Atlantic Hammer- 

 heads, apparently not maturing at a length less than about 10 feet and commonly growing 

 to 13 to 14 feet, with individuals of 1 5 feet reliably reported. 



Developmental Stages. It is not known whether tudes is ovoviviparous or viviparous; 

 30 to 38 embryos have been found in females off southern Florida. Embryos ready for 

 birth differ from adults in the relatively greater length of the hammer relative to its 

 breadth, much larger eyes, longer head in front of mouth, shorter gill openings, more 

 rounded pectoral and caudal, and more oblique and more rounded first dorsal. 



Habits. Nothing is known of the habits or diet of tudes to set it apart from the 

 diflana-zy gaena group. Around southern Florida females have been taken in June. 



Relation to Man. The Great Hammerheads that are taken in the shark fisheries of 

 Florida and the West Indies are utilized with others for leather, etc. Now that shark liver 

 oil is in demand for its vitamin content, large specimens of tudes may prove very valuable, 

 for some (but not all) are extremely rich in Vitamin A. As an example we may cite a 13- 

 foot 1 0-inch Florida specimen which was recently caught and whose liver oil had a 

 potency of 357,000 units of Vitamin A per gram with a sale value of about $500 at 

 current prices. But this was exceptional. Another of about the same size, caught at the same 

 locality a few days later, had a Vitamin A potency of only about 55,000 units per gram, 

 although it yielded about three times as much oil, its market value thus being only about 

 $150." 



Range. Tropical and subtropical Atlantic. Hammerheads have also been reported as 

 tudes from the west coast of Central America, the Hawaiian Islands, Australia, Indo- 

 China, the East Indies, the Philippines, India and the Gulf of Arabia.^" But whether or 



29. Personal communication from Stewart Springer. 



30. See Fowler (Bull. U.S. nat. Mus., loo ['j], 1941 : 213) for a list of Australian and East Indian citations. 



