■2 ME. T. SCOTT ON EXTOMOSTKACA 



nccuracy as well as their beauty, add greatly to its value. My son also prepared the 

 greater number of the dissections represented by the drawings, which were necessary for 

 the satisfactory diagnosis of the various species recorded. 



The Entomostraca described in the following Catalogue include species belonging to 

 the orders Copepoda, Cladocera, and Ostracoda. The first is represented by one 

 hundred and forty-eight species, the second by two species, and the third by twenty-four 

 species. 



The great tendency to, and multiplicity of, variation observed, especially in certain 

 groups, has caused considerable difficulty in deciding the value that should be placed on 

 the amount of variation met with. Thougli care has been taken to avoid as far as 

 possible attaching a higher value to these variations than they deserved, it has been 

 necessary in not a few instances to give them specific and even generic rank, in order to 

 dispose of them in anything like a satisfactory manner. 



A considerable number of more or less immature forms occurred in nearly all the tow- 

 nettings, and were the cause of much trouble during the examination of the material ; 

 the liability of mistaking an immatui'e specimen of one species for a member of another, 

 and a different one, is considerable, and has to be kept constantly in view during the 

 examination of such small organisms. 



Since writing this E,eport I have, through the kindness of Dr. T. Wemyss Fulton, of 

 the Fishery Board for Scotland, been favoured with a perusal of Dr. Giesbrecbt's excel- 

 lent work on the Mediterranean Copepoda, which has enabled me to make some 

 alterations that will l)ring it more into conformity with recent views on the nomenckiture 

 of that important group of the Crustacea ; while the Introductory Remarks by 

 Mr. Rattray, which follow, will add to its completeness. 



Introductory Remarks. By John Rattray, B.Sc, F.R.S.E. 



For the opportunity of taking part in this expedition, of the results of Avhich a report 

 on the Entomostraca is now presented, I have exclusively to thank Dr. John Murray, 

 of H.M.S. ' Challenger ' Commission. J. Y. Buchanan, Esq., formerly chemist on board 

 H.M.S. ' Challenger,' accompanied the expedition, and all my Avork was carried on 

 under his immediate supervision on board the S.S. ' Buccaneer ' (Captain Thomson, 

 R.N.R.), then in the service of the India Rubber, Gutta Percha, and Telegraph Works 

 Co., Ld., of Silverto"v^^l, Essex, and at that time engaged in sounding-operations 

 preliminary to the laying down of a telegraph-eable on the West Coast of Tropical 

 Africa. 



Sailing from Liverpool in the S.S. ' Nubia ' in the begimiing of December 1885, the 

 ' Buccaneer ' was joined by Mr. Buchanan and myself at Sierra Leone on December 23, 

 and sailed at once northwards, touching on Dec. 24 at Bullama and Bassao, between 

 the Isles de Los and Dakar, near Capo Verd, arriving at Dakar on the evening of the 

 same day to complete preliminary arrangements for the soimding expedition, which 

 started thence on December 29. 



