[87] MATERIALS FOR A HISTORY OF THE SWORD-FISHES. 375 
64.—ON THE YOUN G OF THE SWORD-FISH AND SAIL-FISH.* 
By Prof. Cur. LUTKEN, of the University of Copenhagen. 
[Translated by Dr. TARLETON H. BrEAn.] 
For some years past I have had oceasion to occupy myself with the 
Sword-fishes and the requirements for a critical examination of the gen- 
era and species of this group.t Such an examination is certainly pre- 
carious, since the material for it must be sought to a great extent in 
the literature, and can be based only in small part upon an examina- 
tion of the Satire object itself. Without this it will, as a matter of 
course, be impossible, and the more meager the material at hand the 
more uncertain must the result be. This is one of the cases in which 
one cannot entirely neglect such examinations, but must prosecute them 
as thoroughly as possible; only one must always recognize clearly where 
are the limits of reasonable certainty and when these limits are over- 
passed. The approximate result at which I think we must arrive is 
this: that the genus Yiphias (with its single species, X. gladius) cannot 
be considered as the peculiar type of the Sword-fish, as the central point 
of the group, but rather as one of its more divergent, peripheral, or 
strongly “differentiated” forms; that of the round-billed Sword-fish fur- 
nished with ventral fins two genera may be maintained, Histiophorus 
and Tetrapturus, but that in each of these can be established with cer- 
tainty only two species, H. gladius and gracilirosiris, T. belone and 
Hersehelit ; that the genus Machera (round-billed Sword-fish without 
ventrals), on the contrary, must be regarded with suspicion and as re- 
quiring further confirmation. Whether the future will show that this 
reduction of species is too radical must be determined later; but if more 
species than those mentioned are truly valid, the limits between them 
must be detined by more positive characters than have been stated hith- 
erto; and to this end it is necessary that museums shall become richer 
in these forms than there is, perbaps, a prospect of for a long time to 
come. So much is then, at all events, certain, that the two examples 
4 and 18 inches long of the “ species” established as Histiophorus immac- 
ulatus, Riipp.,t and H. pulchellus, C. & V., cannot claim to represent dis- 
tinct species, but merely young forms, stages of development; and one 
may certainly with strong probability refer the little “H. pulchellus” to 
H. gladius or H. orientalis, and thereby unite this specific type with the 
much younger Histiophori, which Dr. Giinther has figured and described. 
In his first contribution (Journal of the Museum Godeffroy, second part, 
p- 170) Dr. G. describes and figures three small fish of 9, 14, and 60 mil- 
* Vidensk. Selsk. Skr. 5, Rekke, naturvidensk. og math. Afd. xii, 6, pp. 441-447. 
tIchthyographiske Bidrag, iv. On the Round-billed Sword-fish, especially on His- 
tiophorus orientalis, Schl. Vid. Medd. Nat. For. 1875, pp. 1-21, with a postscript, p. 243, 
1877-78. 
t A specimen 5 feet 9 inches long is mentioned by Day, Fishes of India, p. 199. 
