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. 



•691. 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 or Ranckiu" 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 dorsally at the point where 

 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 

 into a three-lobed, nearly horizontal fin. 



1 Ahlfeld, F., Mush. d. Menschen, 1880. 



2 Partsch, Brest. 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. Anat. Surg. Soc. 

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

 Army. 



4 Trelat, Gaz. des H6p. t 1869, No. 125 [for others v. Ahlfeld, Abschn. n. p. 175], 



5 Wagner, J., Mull. Arch. Anat. Phys., 1861, p. 735, PI. xvn. A. 



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



7 Watase, S., Jour. Imp. Coll. Sci. Tokio, i. p. 217, Plates. 



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