PISCES FISIJES* 



Skin. - - The small scales which cover the body are 

 developed in the dermis, and are without any bone cells, 



u'.g.a 



FIG, 257. The haddock. 



op 



;/.., Nasal apertures (double on each side); d.f^., d.f'-., d.>'f\>i 

 dorsal unpaired fins ; c.f., the caudal fin of the homocercal tail. 



/>., Barbule ; op., operculum covering the four gills; br.in., con- 

 tinuation of the gill-cover forming the branchiostegal mem- 

 brane ; pv.f., pelvic fin ( = hind-limb), note its jugular position 

 in front of/./!, the pectoral fin ( = fore-limb). 



a., Anus; g:, genital aperture; it., urinary aperture; a./" 1 ., a.fZ.,' 

 unpaired anal fins. it! 0:1 



Their free margin 'is even, a characteristic to which the term 

 cycloid is applied, in contrast to ctenoid, which describes those 



FlG. 258. External characters of a Teleostean 

 a carp (Cyprinus carpio). After Leunis. 



A"., Dorsal unpaired fin ; S., homocercal caudal fin ; A., anal fin ; 

 B., B., pectoral and pelvic paired fins. Note also the lateral 

 line and barbule. 



scales which have a notched or comb-like free margin. Over 

 the scales extends a delicate partially pigmented epidermis. 



