35 



and sometimes in the distribution of bands, stripes, &c. In 

 many cases, the learned doctor goes much further, and supposes 

 even these forms to be subject to such variations as no specific 

 characters would remain, and so, only to quote one example, to 

 have the satisfaction of uniting the gonorhynclms of the Cape 

 with those of Japan and of Australia, he is obliged to suppose a 

 sort whose proportions vary according to age, which sort does 

 not exist. 



I also think that Dr. GTunther shows too little attention to 

 the geographical distribution of fishes. He delights in stating 

 that a sort from the Northern Sea is found at the Cape of Good 

 Hope; that anothor from the coast of Senegal inhabits also the 

 Antarctic Sea. Even fresh-water fishes, whose habitat had, till 

 now, been considered as very limited, are submitted by him to 

 the same process, and sorts from tbe rivers of Chili are united 

 with those of Tasmania, or English sorts are said to be found in 

 New Zealand. In many cases he asserts that they are not entirely 

 similar, and even goes so far as to propose names for those 

 varieties, but nevertheless they must be included under the same 

 specific names. He seems to admit too easily new localities, 

 and so, to give one example, the largest of all fresh- water 

 fishes, the JPirarucu (sudis vastres), is said, on the authority 

 of a dealer, to inhabit Bahia, without telling us what 

 river of that locality is capable of feeding such a giant. 

 The truth is, that it is restricted to the Amazonas and to its 

 northern branches. It is also found in those of the rivers of 

 Guyana, whose head waters, during a part of the year, or at least 

 in floods, communicate with the branches I have just mentioned. 



The old authors, such as Bloch, Lacepede, &c, never hesi- 

 tated to state that a species inhabited Greenland and India ; 

 but under the scrutiny of Cuvier and Valenciennes these sweep- 

 ing assertions generally proved incorrect, and new ideas were 

 introduced on the distribution of sorts in the waters of the world. 

 But after having studied Dr. Gunther's work with the attention 

 it so well deserves, one finds onself once more wandering in a 

 complete sea of uncertainty, and it will take years of careful 

 study to re-establish some rules in this part of geographical 

 zoology. This I consider as the greatest fault in Dr. Gunther's 

 most valuable work. 



