Mitseum contains at the present tune altO(jether b\ll species, rehire- 

 sented hy 29,275 examples*. 



" Rich as this Collection is in the possession of rare and fre- 

 quently unique types, and however well merited its claim to take the 

 first rank among ichthj'ological collections, it must be admitted that, 

 containing not two-thirds of the known species, and on an average 

 scarcely six examples of each species, it is capable of considerable 

 enlargement and improvement. A species to which no particular in- 

 terest is attached ought to be represented by at least three specimens, 

 as a certain number of examples are necessary to fix specific charac- 

 ters. But there are a number of other fishes which cannot be per- 

 fectly understood without a much greater number of examples. 

 Such are those which undergo with age changes so considerable 

 that the stages of development liave been described as different 

 genera, or those which exhibit most extraordinary sexual differences, 

 or are so subject to variation as to have given rise to the creation 

 of numerous nominal species, or those which have a wide geogra- 

 phical distribution. Take, for instance, the Herring. Numerous as 

 the specimens are in the Collection, they only exemplify the various 

 stages of growth of the Herring of the south coast of England and 

 of the Firth of Forth ; they offer evidence as regards the truth or 

 imperfection of the accounts left to us by Yarrell and Parnell ; they 

 indicate that the Herring attains somewhere (probably in the north) 

 to the size of a large Mackerel (15 inches), whilst it exists in a de- 

 generated condition in the Baltic ; they also give us the means of 

 showing the identity of the English Herring with that of North- 

 Eastern America. But there are no specimens exemplifying the 

 various kinds distinguished by professional herring-fishers, none 

 to show the extent of its distribution towards the north or south, 



* "The species and examples are distributed among the eight volumes thus: — 



S|)ecimens Species 



Vol. enumerated. since uflded. in Brit. Mus. since added. 



1.(1859) 2508 177J 475 211 



11.(1860) 3178 1269 531 198 



111.(1861) .... 2625 iOol 5:i6 133 



IV. (1862) 2877 1119 651 174 



V. (1864) 1811 535 492 151 



VI. 1,1866) 2173 278 268 34 



VII. (1868) 3328 283 583 .57 



VIII. (1870) 4461 683 0" 



