162 Prof. M'Intosh's Notes from the 



perform, seeing that the coelomic fluid is present in every 

 branchial filament. 



The effects of inbreeding can hardly affect the reproductive 

 processes of this species, since the sperms are widely dis- 

 tributed in the water and fertilise, it may be, different ova 

 either in the cceloin or in the free condition, whilst the buds 

 form a further check of importance. Notwithstanding the 

 wide range of the sperms shed by such forms in the sea, the 

 question of hybridization does not appear to arise — indeed, 

 no more than in the case of the cod, haddock, and pleuro- 

 nectids which meet on the breeJing-grounds. 



Reversion or atavism appears to have little to support it 

 in the case of Filograna, though the occurrence of a few 

 with opercula in a race usually devoid of tliem may be held 

 by some to indicate this feature, especially as the development 

 of this organ seems to be less connected with the environ- 

 ment. If such organs appeared in a bud — that is, indepen- 

 dently of sexual reproduction, — it might show that the tissues 

 of nurse-stock and bud were imbued with an inherent 

 continuity of plasm, which in function may remain latent 

 or intermittently burst forth in the formation of such organs, 

 just as the reappearance of coloured lonoitudinal stripes takes 

 place in young feral pigs. Particular crosses may also favour 

 the appearance or disappearance of opercula, enlarged tips to 

 branchiae, or other features in succeeding generations : as 

 Darwin says " That a being should be born resembling in 

 certain characters an ancestor removed by two or three, and 

 in some cases by hundreds or even thousands of generations, 

 is assuredly a wonderful fact." As Filograna is lierma- 

 piirodite the so-called secondary sexual characters have a 

 more direct line of transmission. 



Whether the variations noted are hereditary is still an 

 open question, though it would ap})ear that in some cases at 

 least these are not sufficiently stable to lead to the formation 

 of species. Certainly Filuyrana is under '• conditions of 

 life incessantly inducing fresh variability " {Darwin)^ and 

 thus, perha])s, has a check to inheritance in the ordinary 

 >ense of the term. Perhaps the species falls under ihe 

 grou|) in which selection has not been applied, and thus 

 distinct races or even species have not been conspicuously 

 formed ; certainlj' it is difficult to see how natural selection 

 affects Filograna to any extent. The variability in this 

 species is not due to crossing, food, climate, or inbreeding, 

 it is inherent. 



I 



