FISH-CULTURAL INVESTIGATIONS AT ST. ANDREWS, SCOTLAND. 243 



The pelagic ova of the cod — procured during the trawling expeditions of 1884 — 

 were among the earlier forms treated at the laboratory, and every year since have been 

 under observation. The same may be said of the eggs of the haddock and whiting. 



The pelagic eggs of the poor cod (Gadus minuius) have also been frequently 

 under observation, but fertilized eggs about which there could be no doubt have only 

 recently been obtained, as detailed in the accompanying pages. 



The pelagic ova of the ling have been fully described and the larvae and subse- 

 quent stages figured. The ripe ova and milt were obtained from the distaut offshore 

 waters by the long-liners, and though the surroundings of the jars were by no means 

 favorable in the fishing boats no difficulty was experienced in conveying them to the 

 laboratory for hatching. 



The pelagic eggs of the torsk (Brosmius brosme) in a fertilized condition were 

 only recently procured from Shetland, and are distinguished by their pinkish oil- 

 globules, as described in the following pages. 



Great uncertainty prevailed concerning the eggs of the sand eels, both larger and 

 smaller, but it has been found that the ova are demersal and adhesive, probably 

 sticking to sand or other substance in the sites frequented by the adults. The eggs 

 of the larger sand-eel (Ammodytes lanceolatus) have a deep-greenish oil-globule, that 

 in the eggs of the lesser sand-eel being paler and with a pinkish hue. The larvae 

 have long been known, and occur in great numbers in the bottom tow nets. They 

 also, however, at a somewhat later stage are occasionally found at the surface. 



The pelagic eggs of the long rough dab (Hippoglossoides Umandoides) have been 

 familiar since 1884, and every season have been hatched at the laboratory. The egg is 

 remarkable for the size of the perivitelline space, which gives it a large diameter. 



The pelagic ova of the brill have been successfully hatched, and the boldly colored 

 larvae described. The difficulty is to get a sufficient number of ripe ova and a suitable 

 male for fertilization. The egg has a single oil-globule. 



The pelagic eggs of the sail-fluke (Arnoglossus megastomd) also have a single oil- 

 globule, and they and the larvae are described in the following part of this paper. 



The large pelagic ova of the plaice have long been familiar at the laboratory as 

 one of the earliest captures of each season. The ova are hardy and the larvae are 

 easily reared. The growth of the young is comparatively rapid. 



Large numbers of the pelagic ova of the lemon dab (Pleuronectes microcephalics) 

 have frequently been hatched, and the larvae reared to the late stages. There should 

 be little difficulty in rearing this species in suitable open-air tanks. 



The small but ubiquitous pelagic ova of the dab (Pleuronectes limanda) have been 

 familiar every season since 1884. They are hardy and so are the larvae. The same 

 remarks apply to the eggs of the flounder (Pleuronectes Jles us), which can survive con- 

 siderable changes in the temperature of the water. 



The pelagic ova of the sole (Solea vulgaris) were first observed in the trawling 

 expeditions of 1884, and have been found every season in the bay when carefully 

 looked for. The eggs and larvae are very hardy, and experiments on a larger scale at 

 Dunbar will soon be made with both. 



The transparent pelagic eggs of the sprat (Clupea sprattus) occur in enormous 

 numbers every season. They are easily hatched in the tanks. 



The eggs of many other fishes have, moreover, been examined and most of them 

 described, such as those of the short and long-spined Coitus, biinaculated sucker, 



