the dorsal surfaces are of a pale blue color with a milky tint and the impression given by the 

 coloration as a whole is that of pale blue or gray blue, the name being due to the fact that the 

 coloration ia conspicuously paler than in any of the other species. In the sailfish the deep blue- 

 black portion of the back is broad in extent, while in the shortnosed spearfish the belly is a 

 clear silvery white and the dorsal surface is the color of steel. 



In the white marlin jind the shortnosed spearfish there are no spots or markings of any 

 kind on any part of the body, but in the black marlin, sailfish, and striped marlin there are 

 fifteen or more transverse bands of bright cobalt blue or a cobalt with a whitish tinge. These 

 transverse bands do not extend clear across the dorsal and ventral surfaces but are present only 

 in the middle of the sides. If the fish is left exposed to the air for a long time these markings 

 gradually fade or completely disappear, but if water is poured on the fish and the sides are lightly 

 rubbed the markings will again appear clearly. The markings on the black marlin are much less 

 conspicuous than in the other species. On the first dorsal of the sailfish there are a large number 

 of deep blue-black spots scattered irregularly. 



(c) Head 



On the head portion of the spearfishes the elongated jaws are the most marked 

 characteristic. 



The upper jaw of the broadbill is very long, broad, and flattened, so that in cross section 

 it is an elongated ellipse. The length of the upper jaw nrieasured from the posterior edge of the 

 premaxillary exceeds 0. 7 of the length of the body without the snout. 



In the fishes of the family Istiophoridae the upper jaw fornns a long slender cone, the 

 length of which does not attain 2/5 of the length of the body without the snout. The length of the 

 upper jaw is greatest in the striped marlin and least in the shortnosed spearfish, the proportions 

 of length of the snout to the rest of the body in these two species being 2. 804 and 6. 278 

 respectively. 



Marked differences can be detected among the species in the ratio between the lengths of 

 the upper and lower jaws. In the broadbill swordfish the ratio is 4-1/4, while among the fishes 

 of the family Istiophoridae it varies fronn 1.281 to 2.211, the shortnosed spearfish having the 

 smallest ratio and the black marlin the largest. 



The enninence extending forward from the origin of the first dorsal is not very conspicuous 

 in the broadbill swordfish, but it is generally noticeable in the fishes of the family Istiophoridae, 

 being most marked in the case of the white nnarlin and least developed in the shortnosed spear- 

 fish. This characteristic of the white marlin is shown by the fact that it is sometimes called 

 " katahari " or "square shoulders." 



The branchiostegal membranes or membrana branchiostega in the istiophorids are long 

 and the left and right sides are joined, however, this fusion does not appear in the broadbill. 

 The length of the branchiostegal mennbranes varies among the istiophorid fishes, being shortest 

 in the black marlin, the gills of which can be seen between the branchiostegal membrane eind the 

 pectoral girdle. Consequently, differences in the length and form of the branchiostegal rays can 

 also be seen. 



(e) /sic/ Scales and lateral line 



The broadbill swordfish has no scales and the surface of the body is smooth to the touch. 

 Only the ventral surface in the pectoral region is rough with sonnewhat the feel of shark skin. 

 The lateral line is not developed in the broadbill. 



In the istiophorid fishes the scales are buried in the epidermis. They cover the whole 

 body, but on the head they are to be seen only around the eyes and on the preopercle. The scales 

 are very hard and strong and are elongated, the tips being pointed or forked, however, the scales 



