234 THE SCOTTISH MARINE STATION AND ITS WORK. 



wei'e engaged in similar work, and the -services of Dr. Mill 

 have more than once been secured by the Fishery Board 

 for Scotland, in whose annual reports his woi'k for them will 

 be found recorded. 



Biological Investigations. 



The biological work of the Scottish Marine Station may 

 naturally be considered under two headings — Morphological 

 and Fauuistic. The papers in the former category are 

 nearly all the work of Mr. J. T. Cunningham, who was for 

 a period of more than three years the Superintendent of the 

 Granton Laboratory. During the year 1885, much of his 

 attention was devoted to the study of the development of 

 the herring, for which purpose he not only worked in the 

 Firth of Forth itself, but spent several weeks at the village 

 of North Sunderland on the Northumberland coast. The 

 eggs were collected during nocturnal trips in the herring" 

 boats, and kept whilst developing on glass plates in wooden 

 boxes sunk near the shore, so that they could be examined 

 when required. The time of development and the tempera- 

 ture of the water were carefully observed, and it was found 

 that the eggs hatched in eight days when the temperature 

 of the water varied from 11 "5° C. to 14*5° C. One obscure 

 structure in the herring embryos received Mr. Cunningham's 

 special attention. This is a small rounded cavity, which is 

 known from its discoverer as Kupffer's vesicle, and which 

 appears at an early stage of development between the pos- 

 terior end of the embryo and the yolk ; it is clearly visible 

 on the third day and remains so for eight or nine hours, but 

 cannot be seen on the fourth day. This cavity appears 

 from careful investig'ation by means of sections to be the 

 last rudiment of the cavity of invagination, by which the 

 primitive intestine is formed in all except the lowest animals. 

 The theoretical bearing' of this and other developmental 

 researches has been discussed by Mr. Cunningham in sevei'al 

 papers, which are too technical for abstraction here. 



The " glutinous hag ^' or '^ sucker " {Myxine glutinosd), 



