GLYPHIOCERAS (BEYBJCHOCERAS) MICRONOTUM. 177 



Dimensions. 



Specimens in the Museum of Science and Art, Dublin. 

 Adult specimen (type). Young specimen. 



Diameter of shell . . . 95 mm. . 65'0 mm. 



,, umbilicus (edge to edge) . 25 ,, . 20-0 ,, 



,, ., (suture to suture) 22 ,, . 15"5 ,, 



Height of outer whorl . . 45 ,, . 27'0 ,, 



,, above preceding whorl . 25 „ . 18*0 ,, 



Thickness at umbilical margin (about) . 58 ,, . 40'5 ,, 



Affinities. — In his description of this species Mr. Crick has not ventured to 

 suggest any comparison of it with others, and it is in fact difficult to institute 

 any satisfactory one, so distinct does its principal feature prove to be, that is, the 

 extremely globose form of its whorls. In considering its affinities in a more 

 comprehensive sense the character of the suture-line indicates these to be with 

 Beyrichoceras rather than MUnsteroceras. The suture-line of G. (II.) truncatum 

 (PI. XLIV, fig. 2 c, and PL XLIX, fig. 1-1), e.g., is not unlike that of the present 

 species, and there is another feature in which these species resemble eaeh other, 

 and that is in the possession of broad and very shallow constrictions 1 at irregular 

 intervals on the surface of the cast. 



Remarks.*- Only three specimens of this species are known to me, the two 

 figured on Pis. XLVII and XLVIII, from which Mr. Crick drew up his descrip- 

 tion of the species, and another smaller oik 1 which passed through my hands; all 

 are From the same place. 



Locality.- — St. Doulagh's, county of Dublin. 



Glyphiqceras (Beyrici eras) micronotijm, J. Phillips, sp. Plate XLIV, figs. 5 ,i, I,. 



183G. Goniatites micronotus, J. Phillips. Geology of Yorkshire, pt. 2, p. 234, 



pi. xix, figs. 22, 23. 



1843. J. Morris. Cat, Brit. Foss., p. 180. 



1844. F. M'Coy. Synops. Carb. Foss. Ireland, p. 14. 

 1848. J. H. dimming. Isle of Man, p. 357. 



H. G. Broun. Gesch. der Natur, vol. iii, p. 543. 

 1850. Aganides micronotus, A. cFOrbigtiy. Trod, do Paleont. stratigr., vol. i, 



p. 115. 

 1852. Ammonites micronotus, C. G. Oiebel. Fauna der Vorwelt, vol. iii, p. 171 



1 Two of these are seen cluse together on the specimen figured on PI. XLVII, fig. la, at the 



upper part of the latter. 



