THE HADDOCK. 551 



Their free margin is even, a characteristic to which 

 the term cycloid is applied, in contrast to ctenoid, which 



n.a 



FIG. 292. The haddock. 



n.a., Nasal apertures (double on each side) ; d.f. 1 , d.J 2, d.f*, dorsal 



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

 ., Barbule; op., operculum covering the four gills; br.m., con- 

 tinuation of the gill-cover forming the branchiostegal mem- 

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

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



., Anus ;.., genital aperture; ., urinary aperture ; a.f.l, a.f 2, 

 unpaired anal fins. 



describes those scales which have a notched or comb-like 



FIG. 293. External characters of a Teleostean 

 a carp (Cyprinus carpio). After Leunis. 



/?., Dorsal unpaired fin ; S., homocercal caudal fin ; A., anal fin; 

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

 line and barbule. 



free margin. Over the scales extends a delicate partially 

 pigmented epidermis. 



Appendages. The pectoral fins are attached to the 



