306 K.\MAKICHI KISHTNOUYE : 



elongated aud an-anged as if radiating from the eye. In the S(;oml)rida> thesp 

 scales are especially large and unequal in size. 



The scales of the Scombridse are longitudinally striated near the jiDsterior 

 margin, liesides the striation parallel to the posterior margin. Scales of the 

 Cybiidfe are mostly concentrically striated, and those of the Plecos'.ei are 

 mostly smooth at the surface and have a deutritic lumen inside. Very narrow 

 scales, arranged longitudinally and very thickly together, are fjund on the 

 second dorsal, caudal and sometimes on the external sivrface of the pectoral, 

 contributing to strengthening these fins and at the same time to make their 

 siu'face more smooth. 



Fins. 



The fius are generally well developed, stout, ligid, and are adapted for 

 swift locomotion. Some one says that the fins of the male fish arc larger 

 than those of the female ; but I have no fact material to coiToborate it. Like 

 the development of other organs, fins are also best developed in the Plecostei. 

 In the Scombridffl spines and rays in fius are feeble, slender, and fin-rays are 

 transversely articulated as in most teleosteans. In adult forms of the Cybiida) 

 and the Plecostei, fin-rays :we longitudinally divided at the distal end, but not 

 articulated transversely, except in the genus Grammcdorcijnns and iu the 

 venti'als. The ventral fins therefore seem to play a not very important part 

 in swimming in these fishes. The spines consist of single consolidated rods; 

 but the rays are composed of two lateral hahes. 



The fii'st doi-sal fin may be entirely folded into a groove. The other 

 median fins may more or less be divaaicated in the Teleostei ; but in the 

 Plecostei they are nearly solid, and their form and dimension is little altered. 



The pectorals arj rather high in position, ]Ti-etty well developed, .-md 

 when depressed each of them rests in a shallow depression, the djrsal msu-gin 

 of which generally cjiucides with the line, connecting the ceuti'e of the eye 

 with the lateral median line of the caudal peduncle. 



When the pectorals are iu motion, they are spread out horizontally and 

 then- fore margin lies in a straight line, perpendicular to the axis of the 

 body. TJius when we look at Thunmts germo, swimming in tlie sea, spreading 

 its exti-aordiuary long pectorals, we conceive a dr.igoa-fly in tltglit, hence our 



