Holt and Caldeewood — Report on the Rarer Fishes. 503 



presented by the fin-rays and vertebrae, the more especially since the large Irish 

 female C is a connecting link between the fin-ray formulae of the larger and smaller 

 forms, and probably also in regard to their vertebral formiilse. 



We have accordingly included A. lophotes in our list of synonyms. A 

 further argument to the same effect is perhaps furnished by the absence of 

 any small examples that can be said to belong to A. lophotes rather than to 

 A. laterna. 



Although in this Paper we have given details of no specimens of a less total 

 length than 7*9 cm., we have examined practically all lesser sizes of adult 

 form, and can detect no difference to which specific value could possibly be 

 assigned. The smallest specimens have been described and figured by one of us 

 in a previous number of these " Transactions."* On the other hand it will be 

 argued that no fish exhibiting the characters of A. lopihotes have been recognised 

 from Scandinavian waters, where A. laterna appears to be fairly plentiful. It must 

 be remembered, however, that, previous to 1822, A. lophotes was only known to 

 science from three dried skins of unknown locality ; the number was then increased 

 by the capture of the Lundy Island specimen, and when, in 1890, Cunningham 

 first recorded the abundance of this form on the S.W. coast of England, only one 

 other specimen (from Palermo) had been added, while this Paper furnishes the 

 first record of the existence of the form in Irish waters. Hence it is no slm- on 

 Scandinavian naturalists to suggest that A. lophotes may yet be discovered within 

 the Scandinavian area. 



But there is another consideration which may not be without weight. It is 

 matter of common knowledge that the growth of fishes is greatly affected by con- 

 ditions of food and environment. This being so, may it not be that a species, 

 which, in certain localities, attains a large size, accompanied by developmental and 

 sexual metamorphosis of several structural characters may, in a district less 

 favourable, remain permanently stunted, and fail to exhibit the final metamor- 

 phosis ? 



In the case of the Salmonidse we know that this may happen; and the 

 analogy of this family leads us to a speculation as to the probable factor of the 

 evolution of the secondary sexual and late developmental characters of the scald- 

 fish. We have seen that they are in no way related to sexual maturity, but simply 

 to size. 



The experiments of Sir J. Gibson Maitland (to whom we are indebted for much 

 courteous information in answer to our inquiries), in the breeding of Lochleven trout, 

 have established the fact that the offspring of young parents retain, throughout 

 life, a great similarity to the common brown trout (^S*. fario\ whereas the offspring 



* " Trans. Eoy. Dub. Soc," vol. v. (series n.), p. 75. 



