47 



THE MIGRATION OF THE JOLLY-TAIL OR EEL-GUDGEON, GALAXIAS ATTENUATUS, 

 FROM THE SEA TO FRESH-WATER. 

 By ALLAN R. McCULLOCH. Zoologist, Australian Museum. 



The occurrence of various species of the genus Galaxias in the fresh waters of the several continents 

 ami larger islands adjoining the Antarctic oceans has attracted considerable attention. In spite of the 

 lact that several species have been known to breed, or at least to occur, in the sea. it has been argued 

 that Mich a distribution affords evidence in support of the " Antarctic Continent" theory. Regan, 

 however, has recently expressed the opinion '.- that this evidence is not trustworthy, and the following 

 notes are submitted in support of his contention. 



On 31st August. 191. |. I obtained a dozen larval Galaxias attenuates from a small stream crossing 

 the beach at Freshwater Bay. near Sydney, at a few yards above where it runs into the sea. The 

 water they wire in was quite fresh, but concluding that they were migrating to or from the sea I 

 immediately transferred them to a mixture of half fresh and hall salt water; as this treatment did 

 not affect them they were placed in pure sea-water in abouf fifteen minutes' time. They remained 

 alive and healthy in this for about two hours, though the subsequent handling they received caused 

 the death ol all bu1 two specimens. Vboul three hours after their capture these two were again 

 transferred to a freshwater aquarium, in which they have since lived, being now, four months later, 

 alive and healthy. 



The stream from which they were obtained is a small one, being about six feet wide and only 

 a few inches deep ; in dry seasons it sometimes becomes lost in the sand before reaching the sea, but 

 at the time ol our \isit was running with a comparatively strong current across the sloping beach. 

 Surl breaks along the whole length ol 1 In- beach, and at high tide 11m- »;ms wash some little distance 

 up the stream. \ lew miles ..II -Imrr ,1 strong .uncut runs southward during the greater part of 

 the year, carrying small fishes and other pelagii life long di .1.111 e from the point at which they enter 

 it; this southerly drift has a marked effect on the distribution ol marine life on the coast of New 

 South Wales 



Since the surf breaks directly upon the beach, it follows that small fishes migrating from the sea 

 to fresh water mus1 be considerably tossed about in the waves before entering the stream ; and when 

 passing upstream they must light their way againsi a comparatively strong current before reaching 

 quiet waters. it was, therefore, so surprising to find the delicate larval Galaxias in the stream that 

 it was desirable to prove that they really were migrating, and had not merely been washed down by 

 the force of the current. The following test was therefore made with the assistance of several sharp- 

 eved boys : — 



3)ARRiEK 8- 



SAWiER A 



'. Regan — Trans. Roy. Soc. Edinburgh, xlix., 2, 1913, p. 290. 

 2 . Regan — Brit. Antarct. Exped., Zool., i., 1, p. 40. 



