A treatise on zoology . ^It is, however, quite possible that the more shark-like Pristidaeand Khinobatidae represent a primitive group from which the. ^^^ -^5=5^- FiG. 122. Rhynchobatus djeddensiii, Forsk. Dorsal view, and ventral \iew of the head. (After Day,Fishes of India.) Rajidae, the Torpedinidae, and the Centrobatoidei have arisen asthree diverging branches. Group A. Ehinoraji. The rostrum is supported by a large median cartilaginousprocess of the skull (Fig. 120). The tail becomes slender and thedorsal fins shift back towards its tip. Two longitudinal keelsdevelop along its sides. Pair
A treatise on zoology . ^It is, however, quite possible that the more shark-like Pristidaeand Khinobatidae represent a primitive group from which the. ^^^ -^5=5^- FiG. 122. Rhynchobatus djeddensiii, Forsk. Dorsal view, and ventral \iew of the head. (After Day,Fishes of India.) Rajidae, the Torpedinidae, and the Centrobatoidei have arisen asthree diverging branches. Group A. Ehinoraji. The rostrum is supported by a large median cartilaginousprocess of the skull (Fig. 120). The tail becomes slender and thedorsal fins shift back towards its tip. Two longitudinal keelsdevelop along its sides. Paired prepubic processes are present onthe pelvic girdle (Fig. 121). Family Rhinobatidae. The Lead and triuik are much dejire-ssed,forming a disk produced forwards into a large rostrum ; the very largepectorals do not yet reach the snout (Fig. 122). Their endoskeletal radialsattain neither the rostrum nor the large preorbital processes in the Jurassicspecies. The tail is relatively small, is losing its heterocercal shapeby the reduction of the ventral lobe, but still blends in front with thetrunk. The blunt teeth are closely set on the jaws, and m
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