452 Mr. G. C. Crick on some 



have a nearly radial direction on the lateral area and form a 

 fairly wide and moderately deep hyponomic sinus on the 

 periphery ; the body-chamber with obscure backwardly 

 curved riblets extending from the edge of the umbilicus over 

 about one third of the lateral area; the internal cast has on 

 the first fourth of the outer whorl two constrictions, which 

 arise at a short distance from the edge of the umbilicus and 

 cross the whorl parallel to the growth-lines. 



Dimensions. 



Diameter of shell 90 mm. (100) 



Width of umbilicus (at suture of shell) 24 „ (26-6) 



Width of umbilicus (at its margin) 27 „ (300) 



Height of outer whorl 405 „ (45-0) 



Ditto above preceding whorl 28 „ (3M) 



Thickness of outer whorl 29-5 „ (32-8) 



Remarks. I have seen only one example of this species ; 

 it is in the collection of the Geological Survey of Ireland, 

 and I am greatly indebted to the authorities of the Survey 

 for the loan of the specimen. It is there labelled " Goniatiles 

 Leesoni" but, so far as I know, no description of the species 

 has been published under this name. Unfortunately the 

 suture-line cannot be made out ; but there is every reason to 

 believe that the species belongs to the genus Prolecanites. 



Affinities and Differences. The present species can be 

 readily distinguished from both Prolecanites compressus, 

 J. Sowerby, sp.*, and Prolec. similis, Crick f, by the small- 

 ness of its umbilicus. 



Horizon and Locality. Carboniferous Limestone : Glen- 

 bane East, Limerick, Ireland. This is the same locality as 

 that which yielded the type specimen of L. G. de Koninck's 

 (Joniatites ornatissimus \. 



* J. Sowerby, Min. Conch, vol. i. p. 84, pi. xxxviii., 1813 (EUipsolitet 

 compressus). See also Foord & Crick, " On the Identity of Ellipsolites 

 comjyressus, J. Sowerby, with Ammonites Hensloivi, J. Sowerby," Geol. 

 Mag. dec. iv. vol. i. (1894), p. 11, pi. i. 



t G. C. Crick, Trans. Manchester Geol. Soc. vol. xxiii. pt. iii. 1895, 

 pp. 80-84, woodcut. 



J; L. G. de Koninck, " Sur quelques Cephalopodes nouveaux du Cal- 

 caire carbonifere de lTrlande," Ann. Soc. geol. de Belg. vol. ix., Memoires, 

 p. 55, pi. vi. figs. 3 & 4 (erroneously stated to be pi. v. figs. 3 & 4). See 

 also infra, p. 453. 



