Synopsis It is a well known assertion that for any phylogenetic interpretation, especially of the vertebrate phyla, the organization of the basic structural pattern and anatomical features are the essential base. From Agassiz’s time (1857) the internal skeletal structure and the associated modifications as reflected in the external morphology have been utilized for classifying the families and the genera of fishes. One of the reasons for depending upon the basic skeletal structure, perhaps lies in the consistency of various bones in the particular taxa. Absence or presence of major bone elements, extent of fusion of different bones and also the nature of their interdigitations have all been used as indicators of the taxonomic status of various taxa. The fishes belonging to the family Ariidae have attracted the attention of several workers from an osteological viewpoint (Bhimachar, 1933; Shelden, 1937; Berg, 1947; Bamford, 1948; Berrill, 1950; Karandikar and Masurekar, 1954; Tolentino and Clement, 1958; Srinivasachar, 1958; Bubbs and Miller, 1960; Tilak, 1965; Alexander, 1966; McAllister, 1968; Lenous, 1968). Tilak (1965) published a comparative morphology of the osteocranium and the Weberian apparatus of 14 species of the family Ariidae (=Tachysuridae). Still further information is required so as to have a comprehensive account of the comparative morphology of the osteocranium in various species of the genus Arius.