chap, xviii.] MEDIAN DIVISION: GOLD-FISHES. 451 



Examples of such division in the middle line were, I believe, first 

 put together by Geoffroy St Hilaire, and a very full collection 

 of the evidence seen in Man is given by Ahlfeld 1 . The organs 

 most often divided are the sternum, neural arches, uterus, 

 penis, &c, and of these, specimens may be seen in any patho- 

 logical collection. Organs more rarely divided are the tongue 2 , 

 epiglottis 3 , uvula 4 , and central neural canal 5 . The following are 

 special cases of variation consisting in a median division. 



Division of caudal and anal fins in Gold-fishes. 



Cyprinus auratus (Gold-fish). The following account of the 

 multiple fins of Gold-fishes in China and Japan is taken chiefly 

 from Pouchet 6 and Watase 7 . There is evidence to shew that these 

 animals were first imported to Japan from China. 



Three distinct breeds of Gold-fishes are kept in Japan. The 

 first, called "Wakin" has a slender body closely resembling that of 

 the common carp. The second "Maruko'ar Ranchiu" has a very 

 short body, being in some cases almost globular in shape and 

 in it the dorsal fin is generally entirely absent. The head is 

 usually disfigured by rough-looking protuberances of the skin 

 which often attain a considerable size. 



The third or "Riukin" has a short body with a rounded ab- 

 domen. Of all the breeds, this has the most beautiful tail which 

 is very large and often longer than the rest of the body. 



Gold-fish breeders of the present day can freely produce the 

 "Riukin" or "Maruko" from the "Wakin." Various intermediate 

 forms between the above-mentioned breeds exist. 



In all gold-fishes, irrespective of the breed to which they belong, 

 the tail-fin is, above all other parts, subject to the greatest varia- 

 tion. It is to be found in one of the following three states ; 



(1) It is vertical and normal. 



(2) It may consist of two separate halves ; each of these 

 halves is to all appearance a complete tail and the two tails pass 

 backwards side by side, but are united dor sally at the point where 



I they join the body. 



(3) The two tails thus formed are united by their dorsal 

 edges to a variable degree and their lower edges may be bent 

 outwards, so that the two combined tails come to be spread out 



1 into a three-lobed, nearly horizontal fin. 



T Ahlfeld, F., Missb. d. Menschen, 1880. 



2 Partsch, Bresl. Arztl. Ztsch., 1885, No. 17; Pooley, Amer. Jour., 1872, N.S., 

 cxxvi. p. 385 [from Ahlfeld, p. 119]. 



3 Manifold, W. H., Lancet, 1851(1), p. 10; French, Ann. Anal. Surg. Soc. 

 Brooklyn, N. Y., 1880, ii. p. 271 [not seen], from Cat. Libr. Surg. -gen. U. S. 



< Army. 



4 Trelat, Gaz. des Hop., 1869, No. 125 [for others v. Ahlfeld, Abschn. n. p. 175]. 



5 Wagner, J., MUll. Arch. Anat. Pliys., 1861, p. 735, PI. xvn. A. 



6 Pouchet, G., Jour, de Vanat. et phys., vn. p. 561, PI. xvn. 



7 Watase, S., Jour. Imp. Coll. Sci. Tokio, i. p. 247, Plates. 



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