174 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



its height by the preceding whorl; sides somewhat flattened, peripheral area 

 very distinctly flattened in the young shell with a fairly well-marked rounded 

 margin. 



Body-chamber not seen. The suture-line is described but imperfectlj' figured 

 l)y M'Coy (loc. cit.) ; it is, however, figured by de Koninck (loc. cit., p. 99). Test 

 ornamentetl with fine ti'ansverse lines of sigmoidal form crossed by faint longi- 

 tudinal ridges both upon the sides and the perijjheral area. A series of very 

 narrow and shallow constrictions are dcA'eloped, about ten to a whorl ; these pro- 

 ceed from the region of the umbihcus with a slight, backwardly directed curve and 

 cross the peripheral area, making upon it a broad, backwardly directed sinvis and a 

 well-marked angle at its margin on each side (PI. XL VI, fig. ba). 



Dimensions. 



Young shell from Ballinacarrif^ in 



the Dublin Museum of Science 



and Art (Geological Survey 



Collection). (No. 255.) 



Diameter of shell .... 35'0 mm. 



„ umbilicus . . . 10"0 ,, 



Height of outer whorl . . . 15*5 „ 



„ above preceding whorl . . . 8'0 „ 



Thickness at umbilical margin . . . 22'5 „ 



Affinities. — This species is distinguished from G. Bruirni, M'Coy (p. 175), by its 

 smaller umbilicus, more inflated form, and by its ornamentation. It agrees well in 

 respect to the latter feature Avith de Koninck's specimens as figured Ijy him (loc. 

 cit.), though the umbihcus in the Irish specimens is a little smaller. M'Coy gives 

 only one figure of this species, a lateral view, and therefore the peripheral flatten- 

 ing so well marked in the specimen from Balliuacarriga (PL XLVI, fig. 5) is not 

 exhibited. The present species differs both in sutural characters and in ornamenta- 

 tion, as well as in the flattening of the periphery, from (!. (/>'.) sjihsericum. 



RcniarJcs. — A specimen (PL XLVI, fig. 3) from Kilniallock (county of 

 Limerick), contained in the " Grifiith Collection," has tlie name of this species 

 written upon the tablet on which it is mounted, and it has been doubtfully referred 

 to M'Coy's type (loc. cit.), but if it be this M'Coy's figure is inaccurate, as the 

 imibilicus is represented as being much larger than it is in the specimen. The 

 figure also shows a part of the suture-line upon the last whorl, whereas no trace of 

 this is seen upon the specimen. On the whole, however, it appears to belong to 

 the species to which it has l)een assigned, viz. (1. (//.) spha'ruidnh'. 



Localitie.^. — Ballyrichai-d, county of Cork (No. 4707 — Dublin Museinn of 

 Science and Art, Geological Sui'vcy Collection) ; Kilniallock and Balliuacarriga, 

 county of Limerick. 



i 



