196 
PEOF. D. M. S. WATSON AND MR. E. L. GILL ON THE 
extremely interesting earJy form which we, following Traquair's usage, have- 
referred to as " Ctenodiis interruptus, Barkas." (If Dr. Smith Woodward's 
diagnosis of this species, ' Catalogue of Fossil Fishes,' part ii. p. 254, 
accurately represents Barkas's intention in founding the species, the name 
cannot properly be applied to the specimens in the Royal Scottish Museum 
which Traquair referred to it.) The Sagenodus-\\k% teeth of this fish (fig. 24, 
p. 193) are in the strongest contrast with those of the latest known species, 
C. murchisoni, Ward, from the Upper Goal Measures, which have about 
twenty practically parallel ridges. 
Fig. 27. 
Ctenoclus. Lower jaw, x \. 
A. Reconstruction of lower jaw, from buccal aspect. 
B. Ventral aspect of the same. 
C. Left ramus, outer aspect. 
D. „ inner aspect. 
E. An angular and dentary in natural articulation. From two specimens, 
in the Attliey Collection and the British Museum respectively. 
F. The same, inner surface. From the Atthey specimen. 
(Compare figs. 11 and 12, pp. 178, 179.) 
Fritsch's Ctenodus tardus from the Brandschiefer (Lower Permian) o£ 
Bohemia, represented in his Taf. 80 b, is apparently a Dipnoan ; but if his 
drawing of the bones of the skull-roof is at all accurate, it was certainly 
neither a Ctenodus nor a Sagenodus. 
