For critical remarks, see Traquair, Brit. Ass. Reports, 1900, p. 776 et seq.
Compare Figs. 301 and 304.
It is worthy of note that Protopterus dolloi approaches Lepidosiren in the more Eel-like shape of its body, and in the large number of pairs of ribs (54) which it possesses (Boulenger, op. cit. p. 37).
Traquair, Ann. Nat. Hist. (6) vi. 1890, p. 485; Proc. Roy. Phys. Soc. Edinb. xii. 1893, p. 87; ibid. p. 312; P.Z.S. 1897, p. 314; Bashford Dean, Trans. New York Acad. Sci. xv. 1896, p. 101; Mem. New York Acad. Sci. ii. 1900, p. 1.
In a recently published and important contribution to our knowledge of Palaeospondylus, by Professor and Miss Sollas (Phil. Trans. 196, 1903, p. 343), they describe structures on the ventral surface of the head, which they maintain to be branchial arches, as well as others which, in their view, may represent hyomandibular and mandibular elements.