173 
BLOCH’S TOPKNOT. 
Bloch ; pi. 189. 
Ehomhus pimctatns, Yarbell; Br. Fishes, vol. ii, p. 333. 
“ “ Jemyns; Manual, p. 462. 
Pltrynorlioinbus unimcicitlcdus, Gcktiier; Oat. Br. M., vol. iv. 
This species has teen confounded with Muller’s Topknot, 
from which it requires some degree of discrimination to 
distinguish it; and even at this time a considerable amount of 
confusion exists as regards the assignment of their synonyms, 
as well as hi the marks of distinction between them laid down 
by different writers. We have referred to these while speaking 
of the last-mentioned fish, and therefore it is only necessary 
in this place to specify those characters by which it may be 
definitely known, or which may seem to signify some difference 
of habits. In form they nearly resemble each other, but in 
Bloch’s Topknot the width is scarcely so great; the gape is 
more limited, and the bony structure of the jaws and face 
less rigid; but the ridge between the eyes is a little more 
prominent, which, however, will scarcely be discerned unless 
the two fishes are laid side by side. The under side rough, 
but the only unvarjring mark of distinction between them 
appears to be that in the present species the ventral fins are 
visibly separated from the anal, whereas in Muller’s Topknot 
they are united. The colour also in Bloch’s Topknot is 
generally of a lighter cast; but we cannot perceive sufficient 
reason for the trivial name given to it by Eisso and adopted by 
Dr. Gunther, (unhnaculatus , or One-spotted,) since both these 
species are often, and, it would appear, equally marked by a 
defined circular spot at the side, which, however, is sometimes 
not to be perceived. It is probable that the frequent lighter 
colour may be ascribed to its residence on lighter ground; and 
