G. M. Thomson. — Natural Histort/ of Ota<jo Harbour. 241 



Schizoyoda. 



46. Nyctiphanes australis G. 0. Sars. 



This is an extremely common species, and is a valuable food for fish. 

 It is taken in the surface-nets at all seasons of the year, and large quantities 

 have been found in the stomachs of various fish (chiefly hapuka, barra- 

 couta, and ling). 



47. Siriella denticulata G. M. Thomson. 

 Found in the harbour and along the coast. 



48. Tenagomysis novae-zealandiae G. M. Thomson. 

 Common along the coast-line in rock-pools and estuaries. 



Stomato'poda. 



49. Squilla armata Milne-Edwards. (Chilton, Trans. N.Z. Inst., vol. 43, 

 • p. 135.) 



Dunedin. 



50. Lysiosquilla spinosa Wood-Mason. (Chilton, I.e., p. 139.) 

 Otago Harbour, but not common. 



Cuinacea. 



51. Diastylis neo-zealanica G. M. Thomson. 



In 1883-84 I got a few specimens of this shrimp when dredging in the 

 Bay of Islands, and described the species from these (Journ. Linn. Soc, Zool., 

 vol. 24, p. 268). I never met with it again, nor did any other collector 

 find it, till 1906. In June of that year Mr. Anderton learned from the 

 trawlers that great numbers of very large soles and flounders were being 

 taken in Blueskm Bay. The fishermen thought they were spa^\^ling, and 

 this shows how little dependence can be placed on the observational powers 

 of the average fisherman, as they ought to know by this time that none of 

 the flat fishes spawn till well on in August. On going out with the boats 

 he found that the fish were following some food into the shallow water. 

 On the trawl-net being hauled on board immense numbers of small shrimps 

 were found on the deck, on the trawl-ropes and net, and the fish were gorged 

 with them. They all proved to be Diastylis neo-zealanica . The species has 

 not been met with again. 



This case furnishes an example of the remarkable and gigantic migra- 

 tions of organisms which take place in the ocean, of which we know neither the 

 cause nor the location from which the animals come, but which all naturalists 

 who have collected with the dredge or the trawl-net in these southern seas 

 are not unfamiliar with. Fishermen sometimes affirm that some particular 

 kind of fish which used to be common has been fished out, and has entirely 

 disappeared or become rare. The first statement is obviously absurd, as 

 all the fishermen in the country could not fish out any portion of the ocean- 

 floor. But that species of fish and other organisms come and go in a way 

 not capable of explanation in our present limited state of knowledge is an 

 obvious fact, and shows the need of regular and continuous recording of 

 observations such as are now being carried on at the Portobello Hatchery. 



