PBRICYCLUS LEESOiM. 153 



suture-line must nut l)e relied upon too much for diagnostic purposes, but rather 

 the ornamentation of the shell, and also the absence of a sinus, lateral or peripheral, 

 in the border of the apertuie. If llolzajifel be correct this latter feature casts a 

 further doubt upon the generic ])osition assigned to this species, which clearly has 

 a peripheral sinus. 



LocnlUij. — County of Kildare (exact localit}' luu'ecorded). 



Pkiuctclis ? Lkksoxi, G. C. Criclr, sp. Plate XLVl, figs. (J a — r. 



1899. Prolecanites Leesoni, G. C. Criclt. Auu. Mag. Nat. Hist., ser. 7, vol. iii, 



p. 451, figs. 15 a, b. 



Descrij>fii)ii. — Shell discoid, compressed, luuljilicated ; the greatest thickness at 

 the umbilical margin, about one-third of the diameter of the shell ; height of the 

 outer whorl al)out four-ninths of the same. Numlier of Avhorls not ascertainable ; 

 inclusion nearly three-fourths ; umbilicus rather shallow, with steeply sloping sides 

 and subangular margin (on the cast), its width about two-sevenths of the diameter 

 of the shell. Whorl subsagittate in section, the Avidth nearly three-fourths of the 

 height, indented to about two-sevenths of its height by the preceding whorl ; peri- 

 phery narrow, somewhat flattened, especially towards the aperture, obscurely 

 defined ; sides very slightly convex ; umbilical zone narrow, well defined, sloping 

 towards the centre of the umbilicus. Body-chamber probably occupying at least a 

 complete whorl ; aperture not seen. Test so much eroded as to leave on the sides 

 only oljscure traces of ornamentation, but the indications are strongly in favoui- of 

 the shell having been transversely costated; remains of ribbing are obscurely visible 

 on the sides and more plainly upon the periphery where the test is preserved in 

 places, their direction here indicating a rather deep and narrow hyponomic sinus. 

 As far as can be judged the ribbing seems to have been only slightly curved upon 

 the sides. Two shallow constrictions are present upon the cast, one near the 

 commencement of the body-chandler, the other mure posteriorly situated; tlieii' 

 direction conforms to that of the ribbing. 



Dimensiuiii;. 



Typo specimen in tlio Miiseuin 

 of Science and Art, Dublin 

 (Geolof^ical Survey Collec- 

 tion, No. C. 7-tS). 



Diameter of sluH . . . .90 mm. 



„ umbilicus (edge to edge) . . 27 „ 



„ ,, (suture to suture) . . 24 „ 



Height of outer wliurl . . . 40"5 „ 



„ above preceding whorl . . .28 ,, 



Thickness at umbilical margin . . . 29"5 ,, 



