On the Development of the Food-Fishes. 443 



indicutes some uncertainty on the subject, and my own expe- 

 rience of the species has now led me to conchide that what 

 has been described as the poor- or power-cod [Gad as mi nut us) 

 by several authors is only the young of the bib. Considerable 

 change occurs in the outline of the tins as the adult condition 

 is reached, and the pigment is also increased ; but a large 

 series from various parts of the British seas leaves little doubt 

 as to the identity of the two forms. 



It would appear that the confusion in regard to this species 

 has partly arisen from an examination of preserved specimens. 

 This is probably one of the reasons why they are separated 

 in Dr. Giinther's valuable and laborious Catalogue of the 

 Fishes in the British Museum*. 



It is remarkable that very few males were procured last 

 season, and this out of a large number of examples obtained 

 for examination at the marine laboratory. 



XLII. — Early Stages in the Development of the Food-Fishes. 

 By Edward E. Puince, St. Andrews Marine Laboratoryt. 



During the spring and summer of last year (1885) tlie ova 

 of about twenty species of shore and deep-sea Teleosteans were 

 studied in the Marine Laboratory, St. Andrews. Of these 

 about half were carried through the embryonic stages in the 

 tanks of the laboratory, and several species liave, for the first 

 time, been studied and the embryos reared at St. Ancfrews. 

 Six of the species referred to have claimed special attention 

 on account of their economic importance, and the following 

 observations refer mainly to these, viz. : — Gadus merlangiis^ 

 Gadus ceglefnuSj Gadus morrhua, Trigla gurnardaSj Pleuro- 

 tiectes flesus, and Pleuronectes limanda. 



So far as investigations at present show, this remarkable 

 fact has been established — that, with the notable exception of 

 the herring, the ova of those marine fishes which are of chief 

 commercial value are pelagic, and when mature present almost 

 identical features in structure and appearance. In the course 

 of development likewise few points of dissimilarity appear ; 

 but the warning expressed by Prof. Ray Lankester is none 

 the less just, that each form should be investigated in detail, 

 for " in embryology the practical lesson is daily being more 



* Vul. iv. pp. 335, 33G (18G2). 



t Communicated by the Author, having been read at the Aberdeen 

 Meeting of the liritish Association (Section D), September 1885. 



