GLYPHIOCERAS (BEYKICHOCERAS) DIFFICILE. 171 



apart in (I. rotella. The rotundity of the periphery and the smoothness of the test 

 are the same in both species. G. (//.) complanatum, de Koninek, 1 bears also 

 some resemblance to the present species, but it is a more slender shell and 

 the septa are much closer together. The smooth test, rounded periphery, more 

 inflated sides, and distant septa distinguish the present species from G. (/>.) subtrun- 

 catum, though in spite of these differences, which are rather of degree than of kind, 

 the resemblance between the two species cannot fail to be observed. 



Remarks. — -The specific name given to this species refers to the localities 

 whence it was obtained, being in the western part of Ireland. 



Localities. — Ballinacarriga, county of Limerick (301 C, 1519(A); Garrihies, 

 county of Kerry (661 C, 378(3 C., -41 09 C). 



G-lyphioceras (Beyrichoceras) difficile, sp. nov. Plate XLVI, figs. 1 a — c. 



Description. — Shell (cast) discoid, thick, somewhat compressed, the greatest 

 thickness at the umbilical margin. Owing, however, to a peculiar distortion of the 

 shell whereby the upper half is shifted sideways in relation to the lower half along 

 a line bisecting the shell diagonally, this measurement cannot be given accurately, 

 but it represents rather less than one-half of the diameter of the shell ; height of 

 the outer whorl somewhat less than three-fifths of that diameter. Inclusion of the 

 whorls nearly complete; umbilicus small. Whorl subsagittate in cross-section, 

 somewhat higher than wide. Periphery rather narrowly rounded. As the 

 fragment described is entirely septate, nothing is known of the body-chamber, 

 Chambers rather shallow. Suture-line as in PI. XLVI, fig. 1 c. Test unknown, 

 the fragment that remains being too much eroded to show any trace of orna- 

 mentation. 



Dimensions. 



Specimen in the Museum of 



Science and Ail, I hiMin 



(Geological Survey Collection). 



Diameter of shell (cast) (about) . . .70 mm. 



,, umbilicus (about) . . . 10 ,, 



Height of outer whorl (about) . . .42 ,, 



Thickness at umbilical margin (about) . . 33 ,, 



Affinities. Both in its general form and in the conformation of its suture-line 

 the presenl species bears a very striking resemblance to Glyphioceras Hispaniciim, 

 Foord and Crick," and perhaps with better material the identity of the two species 



1 Loc. cit., pi. xlvi, fii^s. 4, 4 a. 



2 'Cat. Poss. Ceph. Brit. Mus.,' pt. 3, p. 190, figs. 91 a~ c. 



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