696 REPORT— 1897. 



■was represented by a gathering. The water was taken in from the sea about 

 14 feet below the surface. AH the material collected was rapidly examined 

 with the microscope while in the fresh condition, and was then preserved in solu- 

 tions of formaline or alcohol for future detailed study. 



The fauna of the area traversed may, from the preliminary examination of the 

 material, be divided into four sections : — 



I. The British Coast fauna — through the Irish Sea and round the north coast 

 of Ireland. 



II. The Oceanic North Atlantic fauna, including Globigerinu, Radiolaria, and 

 other characteristic forms. 



III. The Labrador Current fauna, with quantities of large northern Copepoda 

 and Amphipoda. 



IV. The North American Coast fauna — somewhat like that of the first section. 



[Further details in regard to the characteristic forms in the various gatherings 

 were given at the meeting ; but that preliminary account will now be replaced bv 

 the fuller description of the material to be published shortly.] 



This method of collecting samples of the surface fauna in any required quantitv 

 per day or hour from an ocean liner going at full speed was first practised, I 

 believe, by Dr. John Murray, of Edinburgh. The method is .simple, etfective, and 

 inexpensive. It requires no complicated apparatus, there is no difficulty in the 

 manipulation, and no trouble to speak of need be given to any of the ship's com- 

 pany. It is not even necessary that the naturalist should himself go the voyaoe. 

 The ship's surgeon or any other officer interested in science can readily carr}' out 

 the work ; and so, at very slight expense, series of gatherings can be obtained across 

 the great oceans in every direction traversed by passenger or cargo steamers. 



Addendum. — During the return voyage, at the end of September, the same 

 process was repeated ; but in addition to the four nets used previously a fifth was 

 tied periodically over the tap in the bath-room, and the sea- water was allowed to 

 How through it for stated periods. This gave intermittent gatherino-s for com- 

 parison with those taken continuously. The bath-room gatherings simply showed 

 small samples of the fuller (twelve-hour) day or night gatherings. 



2. Tlie Determinants for the 2Iajor Classification of Fish-like Vertebrates. 

 By Professor Theodore Gill. 



There is much difference of opinion still respecting the limits of the branch of 

 vertebrates or chordata as well as the classes which compose it. Those which in 

 the present state of our knowledge, seem to belong to it are the Tunicates 

 Leptocardians, Marsipobranchs, Ostracophores, Selachians, Teleostomes (Pisces), 

 Amphibians, Reptiles, Birds, and Mammals. The least widely separated of all are 

 the Reptiles and Birds, and if they are retained as distinct classes the others should 

 also be retained. The division into Ichthyopsida, Sauropsida, and Mammalia fails 

 to express the natural relations of the constituent classes. These relations may 

 be exhibited in the following genealogical diagram : — 



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