14 
NEW OR LITTLE KNOWN EISHES 
6 + 16, the longest If in the diameter of the eye. Axillary pore 
moderate. Brown, lighter below (robustus, stout). 
Length of type, without caudal fin, 278 millimeters.* 
Type in the Queensland Museum, Brisbane. 
Keppel Bay, Queensland. 
The specimen on which I have founded the present species, has 
been the source of no inconsiderable anxiety to me. In two 
important characters it departs materially from the type of Neosilurus 
as exemplified by the typical N. Jiyrtlii, and in both it exhibits a 
marked approach to the Tandanus type. These characters are— 
(1) the presence of dermal filaments on the head and body and (2) 
the approximation in the length of the trunk and tail. Another 
circumstance also requires comment, and cannot fail to strengthen 
the doubt as to the validity of its claim to specific rank, namely, 
that it was forwarded from the same locality, by the same collector, 
and presumably at the same time as an undoubted specimen of 
Neosilurus hyrtlii. When, therefore, it is taken into account that 
both that species and Tandanus tandanus are common fishes of the 
Fitzroy River and its tributaries (which drain into Keppel Bay), it 
will not seem preposterous to suggest that we may perhaps be dealing 
with a hybrid between the two forms. 
Analysis of the species of Neosilurus. 
a. Barbels long, the nasals reaching to the origin of the first dorsal fin. 
1. brevidorsalis. 
aa. Barbels short, the nasals not reaching beyond the eye. 
b. Skir; without filaments ; depth of body Ah or less in the total length ; 
preanal length less than 2| in the same. 
c. Width of interorbital region subequal to that of the mouth ; postmental 
barbel reaching well beyond the gill-opening ; gill-rakers 29 ; first 
dorsal fin as high as the body below it 2. mediobarbis. 
cc. Width of interorbital [region much greater than that of the mouth ; 
postmental barbel not reaching to the gill-opening ; gill-rakers 20 or 
21 ; first dorsal fin not so high as the body below it ... 3. hyrtlii. 
bb. Skin anteriorly with criniform filaments ; depth of body more than 4 in 
the total length ; preanal length 2\ in the same. 
d. Width of interorbital region much greater than that of the mouth; 
postmental barbel not reaching to the gill-opening ; gill-rakers 22 ; 
first dorsal fin not nearly so high as the body below it 
4. robustus. 
* The second dorsal and caudal fins and the extremity of the anal fin are much 
injured. • 
t 
