proportion of body length* to body depth, these proportions being 4.460 for the white marlin, 

 4. 561 for the black marlin, 5. 231 for the striped marlin, 6. 371 for the sailfish, and 6. 881 for 

 the shortnosed spearfish. However, the body depth used here was measured along the curved 

 surface of the side of the body, so in actuality the ratio between body length and body depth should 

 be larger. Experiments on several fish of each species showed that, although there are differ- 

 ences among the species, the ichthyological body depth is 83 to 86 percent of the body depth 

 measured over the curved surface of the side. Because the fishes are so large, it was impossible 

 to measure the body depth as ordinarily used by ichthyologists, and as there is considerable 

 danger of error in converting the measured values to the ichthyological body depth in accordance 

 with the above mentioned experimental measurements, it was decided to use the body depth as 

 measured over the curved surface of the side. 



The black marlin differs from the other fishes of the genus Tetrapturus in that the body 

 tends conspicuously toward a cylindrical form, and the body depth at the origin of the first anal 

 fin is greater than in the other species, being only slightly less than the greatest body depth. 

 The body depth at the origin of the first anal fin is greatest in the black marlin and smallest in 

 the shortnosed spearfish, the ratios between the body length and body depth at this part in the 

 two species being 5.682 for the black marlin and 7.900 for the shortnosed spearfish (plate 1), 



The size of the fish differs among the species, the white marlin attaining the most 

 gigantic proportions. The largest fish of this species encountered by the author during his 

 investigation measured 2, 713 millimeters from the posterior edge of the eye to the caudal 

 peduncle. From the author's data and from the reports of experienced commercial operators 

 it appears that the order of size of these fishes of the family Istiophoridae is white marlin, 

 black marlin, striped marlin, sailfish, and shortnosed spearfish. It is said that there are very 

 large broadbill swordfish, but at Taiwan no specimen greater than 1, 500 millimeters in body 

 length without the sword has been seen (plate 2). 



(b) Coloration and markings 



In the broadbill the dorsal surface is a deep blackish brown, with a bluish tint in the fresh 

 specimen, and the belly is yellowish white. The blackish brown color of the back becomes grad- 

 ually lighter along the sides and the boundary between it and the belly color is indistinct. All of 

 the fins are dark blackish brown and there are no markings or spots anywhere on the body nor 

 do the belly or the opercles have any shining silvery coloration. 



In the fishes of the family Istiophoridae in general the dorsal surfaces are dark purple 

 with an indigo tint and the bellies are shining silver. The boundary line between these two 

 colorations is comparatively clear and fornns a finely serrated straight line paralleling the dorsal 

 profile rather than running along the exact center of the sides of the body. When the fish are 

 fresh and the slime has not yet driad, all of the fins except the first dorsal and the first anal are 

 a deep blue-black color. In specimens which have been exposed to the air for a long time the 

 color of the fins changes to a blackish brown. When dried, the first dorsal and the anal fins are 

 also a deep blue-black, but when they are fresh these two fins are a bright cobalt blue. In spe- 

 cimens which have already been exposed to the air for a long period of time and in which the 

 projecting portions of the first dorsal and anal fins have changed to a deep blue-black color, if 

 the covered portions of the fins are taken out and examined it is found that the covered moist 

 portions are bright cobalt blue and thus it may appear that those portions have a particular mark- 

 ing, however, this color /difference/ is not a marking which appeared on these fins in life. 



The black marlin is so called because the silvery white portion of the belly is covered with 

 a brown slime having a purplish tint and the coloration of the whole body is conspicuously tinged 

 with brown. In white marlin which are fresh and from which the slime has not yet been removed 



* Translator 's note : According to a personal communication from the author, the "body 

 length", where not otherwise defined, is the total length from the "tip of the snout to the caudal 

 peduncle. " 



