Cope.] ^^^ [April 1, 



of the M. Jdbbertii. The crescentic ganoine scales of the muzzle of that 

 species and the M. nilidus are absent from the M. macropoma. 



I owe the opportunity of examining the beautiful specimen which is 

 described above to my friend, Mr. R. D. Lacoe, of Pittston, Pa., whose 

 collection of Paleozoic fossils is so valuable, and has been of such utility 

 to students of the subject. 



(?) HOLOPTYCHIUS FILOSUS, Sp. nov. 



Represented by a large scale which has a peculiar and characteristic 

 sculpture. But a small part, if any, of the proximal border is smooth. 

 There is an area of coarse tubercles whose centre marks the proximal 

 lourtli of the long diameter, and whose vertical diameter somewhat ex- 

 ceeds the longitudinal. From this area there radiate in all directions to 

 the circumference, ridges, of which the proximal are very coarse, but 

 which become finer to the posterior side of the central area. The longer 

 and finer ridges divide dicliotomously at various points as they approach 

 the border, the division being most conspicuous in two lines above and 

 two below the longitudinal middle line. The ridges are quite fine and 

 are separated by spaces rather wider than their diameter, except proximal 

 to the area, where the reverse is the case. 



This species is represented by a mold from which a cast has been 

 made. The distal border is evidently thin, and has been more or less 

 broken, so that its outline is not certainly known. The following longi- 

 tudinal measurement may, tlierefore, require revision at some future time. 



MM. 



Diameters of scale P«"g'^"^^'"^^ <->6^ 



( vertical 65 



Diameters of tubercular area { l^ngitu'^iiial 10 



(. vertical 15 



Width proximal to area 9 



Five distal radii in 5 



It will be observed that this is the equal in dimensions of the largest 

 species of Holoptychius known. Its sculpture serves to connect the 

 species of the H. ?iobUissimus type with those of the group Glyptolepis. 

 The apparent absence of proximal smootli border may be due to accident, 

 as the border is not complete ; but it is, in any case, narrower than in the 

 known species. 



From the Chemung beds of Leroy, Bradford county, A. T. Lilley, I 

 have, like Prof. Newberry, obtained the H. americanus Leidy, and the 

 H. giganteus Agass., from the Catskill beds of Bradford county, Pa., 

 through Mr. Andrew Sherwin, to whom I am under many obligations. 



