344 KAMAKICHI KISHINOÜYE: 



interspinous boues are inserted more than posterior ones. In BestreUiger the 

 iuterspinous bones carrying finlets have their sagittal wings ■well developed. 



In the Cybiidae the lateral wings of the first dorsal interspinous bone 

 gradually naiTow towards the dorsal end. The distal segment of the first 

 doKal intei-spiuons bone is a very small round ossicle. Anterior interspinous 

 bones ai"e obhque, but those behind the middle of the vertebral column are 

 more or less vertical. 



In the Plecostei (fig. 44) the first dorsal interspinous bone is very well 

 developed with the lateral wings tiumed anteriorly, and the anterior sagittal 

 wing is very broad, but the lower part not developed, terminating at the 

 middle of the lateral wings at the axis. Tlie distal segment in the first dorsal 

 is broad and tm-ned over upward, and the dorsal posterior end of the proximal 

 segment is also expanded laterally, except a few anterior intei-spinous bones. 

 These expanded paiis are tmned up, quite like the distal segments. Some ix)steri- 

 or interspinous bones of the fii-st dorsal are laterally compressed and want the 

 lateral wings. In the second doi-sal proper the intei-spinous boues are com- 

 pressed anteroposteiiorly and two of them are generally found in evei-y myotome, 

 instead of one in the first doi-sal. Li the Carangidae t^vo or three interspinous 

 bones are found in one myotome under the first dorsah In each interspinous 

 bono the lateral wings are better developed than the sagittal wings. In the 

 second doisal the distal segment is a small narrow bone, inserted between 

 the bases of the two moieties of each fin-ray. The exterior margin of 

 the lateral wings is strengthened by the development of accessory ridges. The 

 interspinous bones of the anal fin difier more or less fi-om those of the second 

 doi-sal, and resemble rather the first dorsal. The first venti-al interspinous 

 bone is longer than the succeeding bones, and some anterior ones are fused 

 together. Most of them have wide lateral wings but the sagittal wings aie 

 not well developed. The lateial wings increase in width towards the free end, 

 and suddenly converge toward the pointed exti'emity. Two of these iutei-- 

 spiuous bonos ju'e found in every myotome. Interspinous bones of the finlets 

 are quite aMke in the dorsal and anal. They aie more or less rod-like iu the 

 Thunnidao ; but they have lateral as well as sagittal wings iu the Katsuwonidtve, 

 and in the posterior pui the sagittal wings only are developed. The distal 

 segment of the intei'spinous boues of the Eecoud dorsal aud amxl is very small, 



