242 Transactions. — Zoology. 



The cold antarctic flow probably rises as it strikes the 

 shallow water ou the south-east of New Zealand, and, working 

 up the coast, seems to baffle between Otago Heads and Cook 

 Strait with the warm tropical current which washes the 

 northern end of New Zealand, works south into Cook Strait, 

 and down the west coast of the South Island. 



The usual meeting-place is probably somewhere about 

 Banks Peninsula, but after a prevalence of southerly weather 

 fish frequenting the colder waters are found as far north as 

 •Cook Strait. It may be that the meeting-place of these ocean- 

 ■currents is one of the principal causes of the fogs so prevalent 

 about Banks Peninsula, and, after southerly weather, in Cook 

 Strait. 



The migrations of the kanae, or grey mullet, seem to me to 

 indicate the extreme limit of the warmer current, whilst the 

 flying-fish, common enough in the Hauraki Gulf and Bay of 

 Plenty, follows the flow of warmer water. The prevalence of 

 mangrove vegetation in the estuaries in the northern parts of 

 the Auckland Provincial District shows that the seaboard is 

 directly influenced by the warm currents, which no doubt 

 carried the floating seeds of this plant to the coast of New 

 Zealand. 



The kanae do not seem to work further down the coast 

 than the estuaries running into Cook Strait, and I am not 

 aware of their being caught south of Wellington Harbour. I 

 believe they migrate with the seasons between the north of 

 New Zealand and the extreme edge of the warmer current, in 

 the same way that their representatives in the Mediterranean 

 Sea migrate in similar latitudes on the Italian coast. 



II. Eivers, Lakes, and Stkeams. 



The beautiful system of rivers and lakes in New Zealand 

 were recognised by the early settlers as admirably adapted 

 for the well-being of SalmonidcB. In the South Island the 

 rivers for the most part originate among snow-clad mountains 

 of hard rock formations, flowing down through the low 

 country, with shingle bottoms, which form excellent spawn- 

 ing-beds for trout. In parts of the North Island the same 

 formations prevail to a large extent, but many of the rivers, 

 such as the Manawatu, Euamahanga, and Hawke's Bay Bivers, 

 run for the greater length of their course through low country, 

 and are not essentially snow-fed, though some of their tri- 

 butaries are. The question of the chemical constitution of 

 the water has never been carefully gone into, but I am in- 

 clined to think that in many of our mountain torrents and in- 

 land lakes there is a deficiency of salt ; this, however, could 

 only be determined by a careful experimental analysis. 



As the geological formation is the basis of the banks and 



