SUMMARY
Horaglanis krishnai Menon is a blind catfish inhabiting the dug- out wells at Kottayam,
Kerala, South India. Studies on the cranial osteology of the fish show that the bones on the
skull are firmly articulated. The frontoparietal fontanella is very large so that the cranium virtually
lacks a roof. The sphenotics and alisphenoids are hardly recognizable and the orbital
bones are entirely lacking. in osteological features H. krishnai closely resembles Uegitglanis
zammaroni. But in H. krishnai the orbital bones are further reduced or even absent. The
fontanella is larger than that of any other knawn catfish. These two species must have evolved
from the same ancester and have taken up nearly identical ways oflife. The difference between
the skeletons of these two appears to be largely dependent on the relative size of the frontoparietal
fontanella. Its greater development in H. krishnaj brought about a suppression or
reduction of some of the bones clearly visible in Uegitglanis. It would appear that the modification
initiated in Uegitglanis gate red momentum in Horaglanis. These two fishes form a
group distinct from clariids and bagrids but form a connecting link between the two.