254 Messrs. Hancock and Atthey on a new Species 



Platysomus Forsteri^ n. sp. 



We have in our possession considerable portions of three 

 specimens of another species of Platysomus that appears to be 

 undescribed ; they were all obtained at Newsham. Unfor- 

 tunately, the general contour cannot be traced in any of them ; 

 the fins are not present ; and though many of the cranial bones 

 are well preserved, they are all scattered. We shall therefore 

 have to rely mainly on the scales for specific characters. The 

 scales (PI. XVII. fig. 3) however, are, sufficiently marked to 

 distinguish the species from all its congeners, and are in good 

 condition. They are large, measuring nine tenths of an inch 

 in length, including the peg, and two tenths of an inch wide ; 

 they are consequently long and comparatively narrow ; the 

 form is rhomboidal ; the peg is long, and tapers gradually to 

 a fine point ; the smooth anterior margin of the scale is rather 

 wide, the rest of the surface being covered with close-set, raised, 

 longitudinal striaj, which are somewhat undulated and slightly 

 diagonal, passing upwards a little inclined towards the front 

 or smooth border, and becoming finer as they approach it : 

 they very rarely bifurcate ; and new stride are abruptly intro- 

 duced, and do not originate in other striee. 



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

 mandibles are all striated like the scales. The mandibular 

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

 the maxillse 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. stn'atus, 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 

 striffi are coarser and much 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. gihhosus 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 named after G. B. Forster, Esq., of Back- 

 worth, who has kindly granted every facility for the examina- 



