1893.] NATURAL SCIENCES OF PHILADELPHIA. 93 



viduals by breeders and fanciers for breeding purposes. A near- 

 sighted fish is certainly an anomaly, and the name " telescope " fish, 

 in allusion to the protruding eye-balls, becomes a misnomer, since the 

 form of the eye is distinctly myopic and short-sighted, and not 

 hypermetropic or far-sighted as required of an optical organ having 

 telescopic capabilities. These facts go still further to support my 

 assertion that these races of Gold-carp are the most profoundly 

 modified of any known race of domesticated animal organisms. No 

 other domesticated animal, as far as I am aware, shows such pro- 

 nounced evidence of becoming myopic. 



These " telescope eyed " fishes also show evidences of mal-develop- 

 ment of the dorsal fins, and a tendency to have the vertebral col- 

 umn curved downward behind in an abnormal way, producing the 

 appearance of a " hunch-backed condition." Such defective devel- 

 opment of the dorsal together with a hunched back is also not 

 infrequent amongst the other short-bodied and long-bodied double- 

 tailed-races. Such defective development of the dorsal, accom- 

 panied by a hunched back, is also found in partially monstrous 

 trout, some of which have been recently figured by a writer in 

 Forest and Stream (vol. xxxix, p. 562, 1892), from specimens sup- 

 plied by Mr. Creveling, which measured from 6J to 8 inches in 

 length. Since these changes in the development of trout are well 

 known to be associated with injuries inflicted during the early 

 stages of development, the case that I have made out for the origin 

 of the double-tailed races of Gold-fish is thus markedly strengthened 

 by similar facts derived from an entirely distinct family, the Sal- 

 monidse. All of the foregoing evidence consequently compels me to 

 abandon the view entertained by me in an earlier paper 1 respecting 

 the origin of the double-tailed races of Gold-carp, in which it was 

 suggested that the doubling of the anal and caudal was a reversion 

 to a remote ancestral condition in fishes, in which paired lateral-fin 

 folds extended for the whole length of the body. This view involves 

 the conception that the single caudal of existing fishes Avas primi- 

 tively a double organ, which has been produced by the concrescence 

 of a pair of lateral caudals, a doctrine which it is quite impossible 

 to reconcile with the morphology of the tails of normal fishes, or that 

 of the tails of the double-tailed races of Gold-carp. What to my 

 mind makes this view still more improbable is the fact that I find 

 the double tails of these " telescope-eyed " forms completely divided 



1 An eight-limbed Vertebrate. American Naturalist, September, 1887, pp. 862- 

 863. 



