82 MESSRS. HANCOCK AND ATTHEY ON 



minute, close, radiating striee, requiring a good lens to show 

 them. There are also a few distant delicate ridges, extending 

 from the centre to the anterior border. 



Such scales are undoubtedly in an imperfect condition. When 

 complete, they are considerably thicker, and the under surface 

 has a smooth bony appearance, exhibiting nevertheless decided 

 concentric lines of growth, a subcentral elongated boss, and nu- 

 merous small pits, particularly on the posterior portion, which, 

 however, we have never seen in a good condition. On the pos- 

 terior or exposed area there are a few obscure, irregular, radiat- 

 ing ridges, which are rendered still more indistinct by the gran- 

 ular tubercles that are scattered over the surface. The smaller 

 scales, which are usually about If inches long and scarcely 1^ 

 inches wide, have all the characters of the larger scales ; but 

 they are generally more elongated in form, and the minute ra- 

 diating striae are coarser. 



Besides these scales, several bones have occurred at Newsham, 

 which, from the peculiar surface sculpture, most probably also 

 belong to this powerful fish. We were anxious to prove this by 

 comparing them with some authenticated fragment of the bone 

 of Rhizodus showing the surface ornament, but have failed in our 

 endeavour. They agree, however, in this respect so well with 

 the descriptions that we cannot hesitate to assign them provi- 

 sionally to this species. 



Of the two most remarkable bones of this collection, one ap- 

 proaches in form to the malar of the Alligator, and reminds one 

 somewhat of the bone in Asterolepis, considered by Agassiz to 

 be a premaxillary ; * but in our specimen the articular portion 

 is wanting. The other bone is apparently the posterior part of 

 a mandibular ramus with a wide articular process at the hinder- 

 most part, not perfect though very distinctly displayed. The 

 former of these bones is quite 4J inches long, and upwards of 

 one inch wide at the broadest part ; it is thin in front, thickens 

 backwards, and bends rather abruptly down at the posterior ex- 

 tremity, which is broken. Along the under margin there is a 



*Poissons Fossiles du Vienx Gres Rouge, troisieme livraison, p. 95, Table XXXII., figs. 

 IS, 19. 



