16 " THETIS " SCIENTIFIC RESULTS. 



The warm current of water which sets down the Austrahan 

 coast from the north brings in its wake many forms not properly 

 belonging to the fauna of our temperate shores. This current 

 from the tropics is extremely rich in minute forms of animal life, 

 consequently fishes are attracted to, and journey along with it. 

 This current brings to us many tropical fishes such as Nomeus, 

 Schedophilus, Psenes, Monacantlius nitens, and M. fiilicauda. 

 A hitherto unrecorded equatorial species, may now be chronicled, 

 Mr. Whitelegge having at Maroubra Bay secured examples of 

 Chcetodon citrinellus, Brouss. One sign of this approaching flood 

 is given by the gulls which flock down to and pick up the 

 food, as pigeons do wheat. Life on the beach, although plentiful 

 enough, is nothing when compared with that of the open ocean, 

 to realise which one must see the tow net after ten minutes run 

 on a sunny afternoon. 



Vegetable life is also richly developed on the surface of the 

 ocean. Mr. Henry Try on, in an interesting paper entitled " The 

 Sea Scum and its Nature,"* describes how, at times, the sea is 

 covered with a greenish-coloured film, which on investigation 

 proved to be due to the presence of a minute alga or plant of the 

 group Nostocacese. The Red Sea is said to owe its name to the 

 occasional presence of such a scum produced by the allied form 

 Trichodesmium erythrcBum. 



Of pelagic fauna Professor A. Agassiz writes : — "One must have 

 sailed through miles of Salpse, with the associated crustacean, 

 annelid, and moUusk larvse, the acalephs, especially the oceanic 

 siphonophores, the pteropods and heteropods, with the radiolarians, 

 globigerinte, and algse, to form an idea of how rich a field still 

 remains to be explored." Of this wealth of life as food the same 

 author continues : — " A number of the marine animals ultimately 

 depend for their food upon the pelagic fauna. The fishes feed upon 

 the hosts of free swdmming Crustacea, many of which develop with 

 immense rapidity ; these in their turn depend for their food upon 

 smaller creatures floating in the watei", and found everywhere in 

 the track of currents. There can be no better evidence of the 

 mass of food contained in the sea than is afforded by the exami- 

 nation of the contents of a tow-net any night. Poui- the contents 

 into a glass jar, and note the edge of the vessel exposed to the 

 light, — it is covered with Crustacea, annelids, and mollusks ; and 

 examine also the residue at the bottom, — a true broth, consisting' 

 of the carcases of all the minute shore and pelagic animals, and a 

 mass of spores of all sorts of marine plants. This broth is used 

 in the Newport Laboratory to feed young fishes and other embryos 

 kept in confinement." 



* Tyroii— Proc. Eoy. Soc. Qd., ii., 1885, p. 18. 



