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PROF. D. M. S. WATSON AND MR. E. L. GILL ON THE 
and consequently in that work Sagenodus was usually referred to under the 
name of Ctenodus ohliquus. The specific names imbricatus, ellipticus, elegans, 
and others, many of them probably synonyms of obliqims and of Owen's species 
S. imcqualis, were also applied by the earlier investigators to remains of 
Sagenodxis ; and more recently a large number of names of very doubtful 
value have been put forward, founded as a rule on isolated examples of the 
abundant and very variable tooth-plates. 
Fio. 1. 
tab.h. 
occ.f. 
Sagenodus. Dorsal aspect of cranial roof, x f. Mainly from a specimen from the Low 
Main Seam of Newsham, in the Royal Scottish Museum, fr., "frontal" (=frontal 
+ post-frontal?); i.fr., iuterfrontal ; i.tem., intertemporal; na., nasal ; occ./., occipital 
flange; i).nn., prenasal ossicles; 2^1:, "parietal" ( = parietal + dermo-supraoccipital); 
sy., "squamosal"; <«6., "tabular" ( = tabular-l-supratemporal) ; tab.h., tabular horn. 
What has hitherto been known of the structure of Sagenodus was due 
mainly to the investigations of Thos. Atthey and Albany Hancock (1868- 
1875). Important additions were made by L. C. Miall (1881). Fritsch, in 
