ON THE CAUDAL AND ANAL FINS OF GOLD-FISHES. 251 



gold-fish closely resembles a common Carassias. There are all stages 

 of caudal and anal fins intermediate between the normal and the paired 

 states ; thus, the tail-fin with its lower portion alone in a double state 

 (Figs. 20 — 22, PI. XIX), or the anal-fin, with either its anterior or 

 posterior portion double and the remaining parts single, is of quite a 

 common occurrence. These different conditions of the two fins 

 combine in various ways in different individuals, thus giving rise to 

 manifold varieties of form, the typical ones of which are shown in 

 the accompanying wood-cut. 



In series I those forms are shown in which anal fins occur 

 plainly in pairs. The caudal fin however occurs in four different 

 conditions. In Xo. 1 it is distinctly paired, giving rise to the "/owr- 

 lohcd ta'V or the " Yotsuo-wo''^ In No. 2 the two halves of the tail 

 are connected at the dorsal edge, giving rise to the " tri-lobed tail " or 

 the " Mitsu-iüo.^^ No. 3 represents a case in which the caudal fin is 

 double only at its ventral edge and No. 4, a case with a perfectly 

 normal tail-fin. 



In series II forms are represented in which the anal fin is single 

 and median in front but double posteriorly. The caudal fin behaves 

 in four different ways as in the preceding series. 



In series III the anal fin is in a reversed condition fi-ora that 

 represented in series II ; namely its anterior portion is double while 

 the posterior portion is single and median. The caudal fin shows the 

 same variation as before. 



In series IV the anal fin is always single and median, the 

 caudal behaving as before. 



We shall now proceed to make a closer examination of the 

 caudal fin. 



The Caudal Fin. The simplest transitional state from single to 

 double, is seen where the tail, normal in all other respects, has the 



