AQUARIUM. 



143 



rieties of the goldfish. Every con- 

 anese, Corean and Sumatran toy va- 

 ceivable variation in body, head, snout, 

 mouth, eye, color and habit has been 

 developed as a result of the tireless 

 patience and perseverance character- 

 istic of the Oriental, as also changes 

 in the forms and the duplication of 

 fins. 



Experiments with the lower forms 

 of animals have proven that disturb- 

 ances of the eggs, by shaking apart 

 the cells produced by the first cleav- 

 age of the ova, will cause the develop- 



arity was preserved by careful breed- 

 ing and later became a more or less 

 fixed character of the breed, as may be 

 seen in the highly prized Chinese and 

 Japanese goldfishes now successfully 

 bred in the United States. 



Careful examinations of the embrios 

 of these double-finned fishes reveal 

 that the duplicated fins are first laid 

 out as two longitudinal thicknesses or 

 folds, and as these are necessarily con- 

 fined to the anal and caudal fins, are 

 formed along the ventral sides of the 

 post-anal section of the body. At a 



i fc 3 * 5 6 7 89 10 



DIAGRAM OF THE VERTEBRA AND TAIL-RAYS OF GOLDFISHES 



1. Single tail of the common goldfish. 



2. Duplication of ventral edge of single tail. 



3. Tripod tail: upper lobe single; lower lobe in duplicate. 



4. Web tail : two separate tails joined only at the dorsal edge. 



5. Dolphin tail: double tail joined at the dorsal edge and flattened to a horizontal 

 plane. 



6. Fan tail : duplicate, vertical, single tails placed side by side. 



7. Fringe tail: a very long, exactly similar, double tail. 



8. Arrow tail: upper lobe in duplicate; lower lobe single. 



9. Rudder tail: duplicate, horizontal, upper lobe; single, vertical, lower lobe. 



10. Bag tail: double tail joined at both the dorsal and ventral edges. 



ment of two embrios from the same 

 egg and the production of monstrosi- 

 ties ; some with two heads on a single 

 body, others with duplicated extremi- 

 tal parts, and still others without some 

 of these extremital parts and the du- 

 plication of others. By some simple 

 practice, such as violently shaking or 

 other disturbances of the eggs, the 

 Orientals developed double monsters, 

 which did not survive, and others with 

 their fins in duplicate, which peculi- 



later period of development, they form 

 separate duplicate fins placed side by 

 side in their respective proper pos- 

 itions. 



In the natural state, these mon- 

 strosities would not be likely to sur- 

 vive, though this does sometimes oc- 

 cur, for encumbered with auxilliary ex- 

 tremities they would be hampered in 

 their movements and would not so 

 readily obtain food or escape their 

 enemies as their normallv constituted 



