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THE AMERICAN NATURALIST [Vol. XLIII 



second, in plan, and to differ from them but slightly in 

 the detail with which this was carried out. 



These cases of duplication of external organs must not 

 be confounded with the gynandromorph here described 

 since that has both male openings and female openings 

 and not a mere duplication of the openings of one sex. 

 There is so much difference between the male papillae of 

 the fifth legs and the operculate openings of the ante- 

 penultimate legs of the female that we must regard them 

 as two morphologically and physiologically distinct or- 

 gans and their occurrence upon the same animal is not 

 the same thing as the duplication of one set upon one 

 animal. This is true even if there were reason to sup- 

 pose that both kinds of openings may have had some 

 common origin in the past. 



The cases of hermaphrodite crayfishes previously on 

 record were considered by Hay along with most inter- 

 esting new cases. It appears from his paper that there 

 are in crayfishes no known cases of such complete, typical, 

 gynandromorphs as that of the lobster described in 1703 

 as having both external and internal organs of the male 

 on the left side of the body and of the female on the right. 

 All crayfish gynandromorphs, but one, are really either 

 males or else females as regards the gonads, and have 

 added but some of the external organs of the opposite 

 sex. One is a female with a little testis as well as external 

 organs of the male. 



The numerous cases of crayfishes from the southern 

 hemisphere with the external openings of both males and 

 females described by different authors are especially 

 interesting as resembling the gynandromorph of this pres- 

 ent paper, since it was found by Lonnberg, 2 that when- 

 ever the internal anatomy was made out, the animal had 

 either a testis or an ovary, and if there was a testis the 

 normal ducts led to the normal male openings, while the 

 redundant female openings had no internal connections, 

 though the testis did send out an extra duct towards the 



2 Zool. Am., 1898. 



