new or little-known Goniatites from Ireland. 441 



Affinities and Differences. The present species is somewhat 

 more inflated and more widely umbilicated than Pericyclus 

 clanensis * ; it is also more inflated than Pericyclus rotuli- 

 formis j", and lacks the constrictions characteristic of that 

 species. 



Horizon and Locality. All the examples of this species 

 that I have seen are from St. Doulagh's, Co. Dublin, 

 Ireland. Three of these are in Dr. Foord's collection, and 

 one (the largest) is in the British Museum collection 

 (no. C. 298). 



Pericyclus pi icatilis, L. G. de Koninck, sp. 



Goniatites plicatitis, L. G. de Koninck, " Sur quplques Cepkalopodes 

 nouveaux du Calcaire carbonifere de l'Irlande," Ann. Soc. o-eol. de 

 Belg. vol. ix., MSmoires, p. 55, pi. v. figs. 3 & 4 (erroneously stated 

 to be pi. vi. figs. 3&4 (1881)). 



Sp. char. Shell subglobose, rather widely umbilicated ; 

 greatest thickness at the umbilical margin, about two thirds 

 of the diameter of the shell; height of outer whorl about 

 two fifths of the diameter of the shell. Whorls (? number) ; 

 inclusion five sixths ; umbilicus deep, with angular margin 

 and steep sides, about one third of the diameter of the shell 

 in width, exposing the angular edges of the inner whorls. 

 Whorl semilunate in cross-section, much wider than high : 

 indented to about two thirds of its height by the preceding 

 whorl ; periphery broadly convex, imperfectly defined, con- 

 tinuous with the sicks; sides feebly convex : umbilical zone 

 well defined, fairly wide, nearly perpendicular to the plane of 

 symmetry of the shell, but sloping a little towards the centre 

 of the umbilicus. Body-chamber apparently occupvin°- 

 nearly the whole of the last whorl ; aperture not seen/ but 

 (judging by the direction of the growth-lines) the peristome 

 probably nearly straight on the lateral area, and with a very 

 broad and fairly deep hyponomic sinus. Chambers (? depth); 

 suture-line only partially seen. Test ornamented with narrow 

 prominent riblets, which pass from the margin of the umbili- 

 cus in a nearly radial direction over about two thirds of the 

 lateral area, and then turn backward somewhat abruptly 

 forming on the periphery a very broad and fairly deep hypo- 

 nomic sinus ; the interspaces are somewhat wider than the 

 riblets ; the whole surface with very fine growth-lines parallel 

 to the riblets. 



Dimensions. Owing to the distortion of the specimen I 



* See supra, p. 436. f See supra, p. 434. 



