ON THE CAUDAL AND ANAL FINS OF GOLD-FISHES, 267 



three days after it was laid, p.a.f., rudiments of the preanal fold. /,'/' paired 

 postanal folds, d.f, dorsal fold. 



Fig. 27. A gold-fish embryo with vertical fin-folds. 5.5 mm. in lengetli. 

 d.f., dorsal fold, c./., caudal fold, a.f., anal fold, p.«./., preanal fold. ?)./., 

 pectoral fin. An, anus. 



Fig. 28. A gold-fish embryo, 6.5 mm. in length. The preanal fold {j}.' a.'f.'), 

 the anal fold (a.'f.) are double. The latter is continuous with the double caudal 

 fold {c.'f.'). The dorsal fold {d.f.) alone is median and unpaired. 



Fig. 29. A gold-fish embryo, 8 mm. in length. Ventral view, m., median 

 portion of the preanal fold, f.' a.' f, double preanal folds. «.'/'• double anal 

 folds, c.'/'j flouble caudal folds, ^j./., pectoral fin. An., anus. 



Fig. 30. Postanal section of an embryo, in which the ventral fold is double 

 only at the region of the caudal fin {c.'f.'). 



Fig, 31. The same, in which the ventral fold is double only at the region of 

 the anal fin {a.'f.'). 



Fig. 32. The same, in which the ventral fold is double only at its free edge. 



Fig. 33. Posterior half of a young gold-fish, 7.5 mm. in length. This 

 specimen belongs to the breed " Murulco " and does not possess the dorsal fin fold. 

 ■p.' a.'f, double preanal folds, a.'f.', double anal folds (anal fin), c,'/', double 

 caudal folds (caudal fin). 



