66 MESSBS. HANCOCK AND ATTHEY ON 



Ceratodus, but correspond in every respect to Ctenodus, except 

 in the deficiency of tuburcles or denticles on tlie ridges. 



7. Ctenodus ellipticus, n. sp. 



Tooth flattened, thin, elliptical. If inches long, and fths of 

 an inch broad ; the inner and outer margin irregularly arched ; the 

 surface with five transverse, smooth, distant, angular ridges, in- 

 creasing in size towards the outer margin ; the furrows are wide 

 and round, and the anterior and posterior margins of the tooth 

 are extended a little beyond the ridges before and behind ; the 

 whole surface, including the ridges, is minutely punctured. The 

 mandibular tooth is narrow with the inner border gibbous ; in 

 other respects it agrees with the upper or palatal tooth. 



The maxillary bone is considerably more than twice the length 

 of the tooth, and has the posterior extremity greatly expanded 

 and truncated. 



Five or six specimens of this tooth have come into our posses- 

 sion. They occurred at Newsham, and are all fully developed 

 and in good condition. 



This well-characterized species is not likely to be mistaken for 

 any of those above described. The only one with which it might 

 possibly be confounded is C. imhricatus ; but the comparative 

 thinness of the plate and the non-imbrication of its ridges sufii- 

 ciently distinguish it. 



IV. — Notes on the Hemains of sovw Reptiles and Fishes from 

 the Shales of the Northumberland Coal Field. By Albany 

 Hancock, F.L.S., and Thomas Atthey.* (Plates I., II., III.) 



The coal shales of the Low Main Seam at Newsham and Cram- 

 lington, near Newcastle-upon-Tyne, so prolific in fish remains, 

 have also yielded some very interesting reptihan fossils, the 



* Read at a Meeting of the Natural History Society of Newcastle-upon-Tyiie and Tyne- 

 side Naturalists' Field Club, March 12, 1868. 



