GI.VI'IllOCKKAS (MUP]NSTKHOCI^]RAS) KF.LI I'SOI DA I.K. I'.C) 



sevenths of the same. Number of whorls not known ; inclusion about two-thirds. 

 Umbilicus deej), with stec]), nearly vertical sides and sulmngular margin, exposing the 

 edges of the inner whorls, about two-sevenths of the diameter of the shell in width. 

 Whorl very distinctly semi-elliptical in cross-section, height about three-fourths of 

 the width ; indented to nearly one-third of its height ])y the preceding Avhorl. 

 Sides slightly co vex, somewhat flattened near the unil)ilicus ; iiml)ilical zone narrow, 

 slightly concave, nearly perpendicular to the plane of symmetry of tlie shell. Body- 

 chaml)ei' occiqjjing the whole of the last whorl ; peristome with a widely curved 

 lateral crest and broad and deep hyponomic sinus. Test smooth, with faint lines of 

 growth near the aperture. 



Dimensions. 



Typf specimen from Kiklare, in the 

 Musuiiiii of Science and Art, 

 DubUn. 



Diameter of shell .... So'O mm. 



„ umbilicus (edge to edge) . . 23"5 ,, 



,, ,, (suture to suture) . . 20"0 ,, 



Height of outer whorl . . . 36'0 ,, 



,, above preceding whorl . . . 25"0 „ 



Thickness at umbilical margin . . ' . 47'0 „ 



A(jinitit's. — The only species which resembles the present one in any marked 

 degree is that which I have called (/. (il/.) ubesuni, Avhich, being figured upon the 

 same plate, can be readily compared. The form of the shell in each is considerably 

 inflated, and in Ijoth the peripheral lobe of the suture-line has the suljparallel sides 

 characteristic of Muensteroceras. The test in both is smooth. In cross-section, 

 howevci*, the whorl in G. (M.) ellipsoidale is broadly arched above ; in G. uhrsiim, it 

 is narrower as well as Ijeing distinctly flattened — at least in the region of the 

 body-chamber. 



There is not very much difference Ijctweeu them in their umbilical characters. 

 Allowing for the distortion in the specimen representing (I. (il/.) ubcsum, the 

 mubilicus in this species is relatively sniallei- than that of G. (M.) (ilipsoidalc. Its 

 more inflated and smooth shell and larger umbilicus suffice to distinguish the present 

 species from G. striatum, J. Sow. 



Remarks. — Mr. Crick' refers a specimen in the Bi'itish IMuseum (No. ('. 2'.il) to 

 the present species, but with some doubt; it is from the C'arbt)niferous liimestone 

 of Uathkeale. 



Lucalities. — Kildare (exact locality in tlie county unknown) ; Little Island, near 

 ('ork ; (?) Rathkeale, county of Limerick. 



' Loc. cil., p. 450. 



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