IlEllMA-PHRODITE GENITALIA OF THIi CODFISH. 545 



hermaphrodite, the facts above cited are sufficieut to suggest 

 that the hermaphroditic condition, so marked among the Teleostei, 

 may be reyersional to, if not realistic of, that which must have 

 been the ancestral condition for the Chordata*. And if, as 

 seems to me most reasonable, the unicyclic maturation of the 

 ovotestis of the Hag is au abbreviated and specialized equivalent 

 of the multicyclic one of the hermaphrodite Teleosteans, the 

 question arises whether, in view of this, the bony fishes may not 

 have retained a more primitive condition of the genital glands 

 than have the other Gnathostomata f. On this supposition, 

 their frequent i-eversiou to the condition of hermaphroditism 

 becomes at once intelligible, and, indeed, is that which might 

 be expected. 



Brock has shown J: that tiie reproductive apparatus of the 

 Stylommatophorous Pulmonata is laid down upon the female 

 plan, and that the later differentiation of the male parts is some- 

 times never effected. He seeks to apply this principle to the 

 hermaphrodite Teleostei (Joe. cit. p. 374) ; but, from examina- 

 tion of such of the latter as I have been able to obtain, I am 

 strongly of opinion that further investigation will prove him to 

 have been mistaken. 



* Laulauie has attempted to distinguish between successive phases of sexual 

 neutrality, hermaphroditism, and unisexuality, in the ontogenetic development 

 of the genital glands of the Amniota. He institutes comparisous with what he 

 believes to have been the phylogenetic evolution of the organs named, and builds 

 up an argument for primitive hermaphroditism (Comp. Eend. t. ci. pp. 393-395, 

 1885, & Bull. Soc. Toulouse, t. xx. pp. 13-16). Unfortunately, his observations 

 are insufEcient and of too incomplete a nature to justify the full acceptance of 

 his statements. 



i' Experimental researches of the last six years have considerably modified 

 the old belief that access to the sea is indispensable for the maturation of the 

 genital glands of the Salmones. Not only have fish been found in the Parr 

 stage with fuuctional testes, but Day and Maitland have succeeded in rearing 

 young from the eggs of 32 months' land-locked Parr of Salmo salar (Trans. 

 Linn. Soc. Lond., Zool. ser. 2, vol. ii. 1885, p. 447 \cf. also Day's ' British and 

 Irish Salmonidfe,' pp. 101 et seqq.Y)- In view of the above considerations, the 

 probability that the earlier maturation of the genital gland of the male 

 Salmonoid may be the expression of an ingrained tendency towards regular 

 hermaphroditism must not be overlooked ; and I would suggest the same 

 interpretation of the recent discovery by Holt, that in the Mackerel the male 

 organ would appear to be the first to mature (Ti-ans. K. Dublin Soc. vol. iv. 

 ser. 2, p. 437, 1891). 



X Zeitschr. f. wiss. Zuol. Bd. xliv. p. 374 (1886). 



