however, as a result of the examination of a large number of specimens it appears that this is 

 probably in error, at least the fishes of the family Istiophoridae in Formosa all have 3 ventral 

 fin rays (plate 9). 



3. Viscera 



In the fishes of the family Istiophoridae the body cavity is very long, extending posterior 

 to the anus, and its posterior end reaches the area above the origin of the first anal fin. In the 

 broadbill the body cavity is short and wide, and its posterior end is anterior to the first anal fin. 



In the istiophorid fishes the anus is in an advanced position about the length of the first 

 anal base anterior to the anterior end of that fin. 



In the Istiophoridae the stomach is very large, in full specimens reaching almost to a 

 point above the anus. The opening of the intestine appears close to the cardiac orifice and the 

 intestine itself is slender, about the size of one's thumb, and enclosed in the pyloric caeca. This 

 portion of the intestine is somewhat expanded; the intestine then makes a sharp bend, the portions 

 adjacent to the bend lying parallel to each other, and it then makes a slight curve along the tip of 

 the pyloric caeca after which it runs straight to the anus. The length is much less than the body 

 length, the proportions being about 2. 26. The contents of the intestine are simply mucus and it 

 is not possible to discover any solid object with the naked eye. The liver is rather small and 

 covers a part of the pyloric caeca, and the gall bladder is slender and elongated. In a general 

 view this digestive system presents a form extrennely close to that of the tunas. 



The air bladder is very distinctive, being formed of many chambers like a mass of 

 bubbles lying along the dorsal surface of the whole body cavity. The digestive organs and the 

 gonads (except in the shortnosed spearfish) are all contained in the body cavity anterior to the 

 anus, with only the air bladder extending posterior to the anus and reaching a point above the 

 origin of the second anal fin. This is a point of conspicuous morphological difference between the 

 istiophorid fishes and the sconnbroids, which are considered to be most closely related to them. 

 The air bladder is composed of small chambers of irregular size, but the arrangement of these 

 is more or less bilaterally symnnetrical (plate 10). 



The gonads are on the whole bilaterally symmetrical, but in the shortnosed spearfish only 

 they have a peculiar structure, being Y-shaped with the right side short and its posterior end 

 joined to the left side. The point where the two gonads are joined is ilirectly above the anus and 

 they open through a single short reproductive duct. The left gonad is prolonged posteriorly and 

 in well-nnatured specimens it reaches the posterior end of the body cavity. 13/ 



The tip of the ureter is markedly expanded, forming a part which might be called a uri- 

 nary bladder. 



In the broadbill the body cavity is short and capacious and there is no marked difference 

 from the istiophorid fishes in the structure of the digestive tract. The body cavity appears only 

 anterior to the anus, the stomach is large, the liver is small, and the pyloric caeca are also 

 markedly smaller than in the Istiophoridae. The form of the intestine is somewhat different, the 

 flexed portion being notably shorter, and differences in thickness are apparent from the anterior 

 to the posterior end. In the istiophorids a cross section presents a regular round shape, but in 

 the broadbill it is irregular with conspicuous indentations zmd projections. 



The air bladder is single-chambered and large. Its nnembranes are weak and it is easily 

 destroyed. 



— Nakamura, Hiroshi. Zoological Magazine, Vol. 49, No. 6, pp. 233-238, 1937. 



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