414 MESSRS. HANCOCK AND ATTHEY 



passing upwards a little inclined towards the front or smooth bor- 

 der, and becoming finer as they approach it ; they very rarely 

 bifurcate ; and new striae are abruptly introduced, and do not 

 originate in other strias. 



The head bones, occipital crest, gill-covers, clavicle, and man- 

 dibles, are all striated like the scales. The mandibular teeth 

 are large, conical, stout, and obtusely pointed ; those of the 

 maxillas are small, conical, and tubercle-like, with wide bases 

 and recurved pointed apices, and are disposed without order 

 along the alveolar border. 



This fine species cannot measure less than P. striatus, and at 

 first sight, so far as the scales are concerned, might be con- 

 founded with it ; but on attentive examination, they are seen to 

 be very different. They are much longer and narrower ; and 

 while these are rhomboidal, those of P. striatus can scarcely be 

 so designated, being more nearly oblong. The striaa are coarser 

 and less oblique in P. Forsteri ; the peg is longer, more slender, 

 and with a sharper point. Indeed, from the form and character 

 of the scales, it would seem that this species is more nearly allied 

 to P. rotundus than to P. striatus. P. gibbosus is distinguished 

 by having some of the cranial bones granulated, which is not 

 the case with our new species ; and, besides, the scales of the 

 former resemble those of P. striatus, according to the figures in 

 Agassiz's "Poissons Fossiles," Vol. II., Tab. 15. P. declivis 

 would appear also to have the scales of similar proportions. 



This species is Darned after Gr. B. Forster, Esq., of Backworth, 

 who has kindly granted every facility for the examination of the 

 shale at Newsham, without which valuable privilege much of 

 our knowledge of the palasontology of the Low Main could not 

 have been attained. 



Amphicentrum striatum, n. sp. 



A new species of this rare and interesting genus has been found 

 at Newsham ; seven or eight specimens have been obtained. It 

 differs by well marked characters from the A. granulatum, Hux- 

 ley, the only other known member of the genus, and it is much 

 smaller. The contour of the new species is rhombic, the trunk 



