In this paper the authors describe a conclusion regarding the result of comparative ob-servations on the pharyngeal bones and their teeth in four subfamilies, eighteen genera and thirty species of Japanese cyprinids.
Though there are some variations, relative length of the pharyngeal is fairly constant, and pharyngeal bone length in standard body length of the fish will make one of specific characters of the fish (Table 1).
In all Japanese cyprinids, the rate of the breadth in the length of pharyngeal bones is in the range of 5.2 ?? 3.0 In general, fishes with long pharyngeals tend to be carnivorous, or fishes with short and broad pharyngeals are usually inclined to be herbivorous (Table 2).
The length of posterior and anterior limbs equal in length in almost all species, or the former slightly longer than the latter, while the anterior limbs longer than the posterior ones in five species of leuciscine fishes.
The rate of elongation to anterior direction of pitted surface of the pharyngeal will make one of specific characters of the fish.
In all species, pharyngeal bones of the fish always having anterior angle, but posterior angle indistinct or not to be found.
Pharyngeal bones having one to three rows of teeth. In the first row with three to five teeth, the second row without or with one to five teeth and the third row without or with two teeth. (Table 5-7)
The authors have established a key to Japanese cyprinids subfamilies according to the characters of pharyngeal bones and their teeth.
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