GLYPHIOGERAS (BEYRICHOCERAS) BROWNI. 175 



GLYniiocERAs (BioYKirnorKKAs) Bkowni ? F. M'Goi/, sp. Plate XLVI, figs. I- " — r. 



IB-ti. GoNiATiTEs Bkowni. F. M'Cuij. Svuops. Garb. Foss. Irelaud, p. 12, \>l. iv, 



fig. 17. 

 1880. — — L. G. de Koninclc. Fauue Calc. Carb. BelL;i(|ue (Aim. 



Mus. Roy. d'Hist. Nat. Belgique, ser. 

 Palcoiit., torn, v), pt. 2, p. 98. 

 1889. (tlyphioceeas Browni, E. Holzap/el. Palseout. Abhandl., Dames uud 



Kayser, Bd. v, i, p. 30. 

 1897. — — A. H. Foord and G. C. Crick. Cat. Foss. Ceph. 



British Museum, pt. 3, p. 183. 

 1899. — — G.C. Crick. Ami. May. Nat. Hist., ser. 7, vol. iii, 



p. 438. 



Description. — The following is M'Coy's description : — " Discoid, subglo])ose, 

 sides flattened; umbilicus large, acute-edged, exceeding one -third the diameter of 

 the shell ; surface smooth ; septa, dorsal lobe small, bifid ; dorsal sinus acute ; 

 first lateral lobe slightly exceeding the dorsal in length, very wide, rounded ; 

 lateral sinus twice as long as the dorsal, acute, linguiform ; second lateral lobe 

 very wide, obtusely rounded. 



" From the G. striatus, Sow,, which the species most resembles, it is dis- 

 tinguished internally by its much shorter and wider first lateral lobe ; the same 

 character distinguishes it irom the (r. spjiserirna, Sow., and from lioth it is 

 distinguished externally by its smooth surface, and from all the species of the 

 same form by the large size of the umbilicus. Diameter two inches two lines ; 

 thickness one inch one line." 



It('inarlc!<. — The type of this species has l^een lost, and thei'e is therefore only 

 M'Coy's figure and description to serve for its identification. A distorted speci- 

 men bearing the name " Goiiiatitcs xphsenndidifi" is contained in the "Griffith 

 Collection," and this I refer with considerable doubt to M'Coy's species. To give 

 its dimensions would be misleading, as its original form has l)een converted by 

 pi'essure into a long ellipse. The principal ground for the determination of its 

 affinities rests upon the size of the umbilicus, which, as in M'Coy's representation 

 of the species, is remarkably large, being approximately one-half of the shorter 

 diameter of the shell and al)out one-third of the longer. The suture-line is too 

 ini[)ei'fect for comparison with the one figured by M'Coy (loc. cit.), otherwise it 

 would have afforded very important information. The test, which is not 

 well preserved, bears upon its surface a few faint longitudinal ridges and 



