SINUITES ? RAMSEYENSIS. 15 



Localities. — (1) Tliraive Glen, Gir van. (2) Tyrone? 



licmnrl-s. — The degree of convexity and rotnndity of tlie dorsnni and ilio 

 breadth and height of the shell vary within somewhat wide limits, scnnc specimens 

 being almost glol)Ose and others somewhat laterally compressed, with almost a 

 tectiform dorsnm ; bnt as all intermediate stages seem to be present, and the 

 apertnral and internal characters completely agree, it is not possible to separate 

 them as definite varieties. One specimen (M. 2888B Geol. Siirv. Mns. Edinb.), 

 shows internal transverse thickenings near the nmbilical edge. 



The general shape of the shell approaches S. hilohatus (Sow.) and the angnlarity 

 of the apertnral lobes is almost identical with S. rectangularis (Ulr. and Scof.),^ 

 which has been also compared with S. maccalliimi from Ardmillan. A similar 

 internal thickening is fonnd in S. cvupticus, Reed,~ and in B. (6*.?) strangulata, 

 Barr,^ and in other species of Sinuites, as above mentioned. 



Ulrich and Scofield have stated (oj). c'lt.) that the rectangular outline of the 

 apertnral lobes in »S'. rectangularis is not possessed by any other species of the 

 same suborder, and is quite distinct from the true 8. hilohatus. But our' species 

 differs from the American one by the closed umljilicus and the transverse internal 

 thickening. »S'. elongatus, Forth, is closely allied. It appears to occur in Tyrone, 

 judging from poor specimens in the Sedgwick and Jermyn Street Museums. 



13. Sinuites? ramseyensis (Hicks). 



1873. Bellerophon 7-mnseyensis, Hicks, Quart. Jouni. Geol. Soc, vol. xxix, p. 50, pi. iii, figs. 30 — 32. 



Specific Characters. — Shell laterally compressed, acutely carinated ; outer whorl 

 embracing inner whorls and rapidly increasing in height to mouth. Umbilicus 

 small, situated at a1)out one-third the height of shell. Mouth high triangular, 

 not expanded. Dorsal sinus V-shaped ? Surface smooth. 



Dimensions. — Height about 6 — 9 mm. 



Horizon. — Arenig Series. 



Localities. — Ramsey Island ; Tremanhire, Pemb. 



Remarks. — This small species, which was obtained from beds referred to the 

 Tremadoc by Hicks but now known to be of Arenig age, was briefly described by 

 its founder as follows: "Broad, involute, with the outer whorl greatly expanded 

 and ridged on the back ; ^ inch in diameter. Surface smooth." The type 

 specimen and other examples of the species are very poor, but the species may be 

 related to 8. discoides from the Balclatcliie Group of Girvan. Perhaps Belleroplion 

 shinetonensis, Callaway,* from the Shineton Shales, is also allied to it. Hicks's 

 original specimen of B. ramseyensis is in the Sedgwick Museum. 



' Ulrich aud Scofiekl, op. cit., p. 868, pi. Ixiii, figs. 15 — 20. 



2 Reed, ' Geol, Mag.,' [5] yoI. iii (1906), p. 363, pi. xx, figs. 12—14. 



^ Perner, op. cit., p. 159, pi. ixxxvii, figs. 12 — 14. 



-* Callaway, 'Quart. Journ. Geol. Soc.,' vol. xxxiii (1881), p. 668, pi. xxiv, fig. 10. 



