319 
head 5, its breadth 17/, in its length, its dorsal profile slightly 
convex, slowly sloping down to the snout, which is bluntly 
conical. Its lower border runs in a somewhat oblique and posterior 
direction to the upperlip, which borders in a semicircle the quite 
inferior mouth. A vertical through the mouth is nearer to the 
eye than to the point of the snout, it is only about '/, of the 
length of the head. The somewhat swollen lips are connected by 
a rather broad fold. Nostrils close together, situated below a 
horizontal connecting eye and point of snout. Crownshield 
with undulating rugae, radiating from a central point. Occipital 
process keeled, '/, longer than broad at its base, its rectilinear 
sideborders converging, its truncate hindborder somewhat 
emarginated and touching the rugous, crescentic basal bone 
Fig. 139. Zetranesodon conorhynchus M. Web. 
of the dorsal spine. Before the crownshield a narrow, oval 
fontanel about as long as snout. Humeral process rugous, 
elongate and truncate. Eye lateral, situated in the anterior 
half of head, 6°/; in head, twice in snout and 2'/, times in 
the very convex interorbital space. Maxillary barbels 2'/, 
times in head, reaching nearly halfway to posterior border of 
opercle, mandibulary barbels '/, longer than eye, mental barbels 
slightly shorter. Mandibulary and mental barbels originating 
close together in one line. Height of dorsal equal to head 
from posterior nostril, its spine slightly shorter, flattened, 
anteriorly with weak, posteriorly with stronger serrations. Base 
of adipose fin longer than dorsal, its distance from dorsal '/, its 
