28 ORDOVICIAN AND SILURIAN BELLEROPHONTACEA. 



Horizon. — Middle Ordoviciaii : Wliiteliouse Group. 



Locality. — Sliallocli Mill, near Grirvaii. 



Bemarlcs. — All the specimens available are more or less crushed and distorted, 

 but the reference to the genus Isosjnra seems certain. The shell is not unlike 

 I. bitcanioides, Koken.^ G. fdanicosta, Pernor,^ G. tnhoides, Barr.,^ G. kokeui, 

 Perner,* and G. eicimias, Barr.,^ are comparable in shape or ornamentation. 



Genus BUCANIELLA, Meek. 



Generic Gharacters. — Shell involute, subglobose with volutions rounded, 

 rapidly enlarging- ; dorsum trilobate or quadrilobate owing to presence of revolving 

 grooves. Umbilicus more or less open, usually deep ; mouth transverse ; outer 

 lip sinuate. No slit-band. Surface with fine growth-strias and occasionally 

 revolving lines. 



The name Bucaniella was proposed in 1870 by Meek" for broad-backed 

 trilobed Silurian species of Bellcrophoii without a slit-band ; and the present 

 author follows Clarke ^ in thus restricting the use of the term. Koken ** would 

 include forms possessing a slit-band, but Ulrich and Scofield ^ (who write the 

 name of the genus Bucanella) definitely state that in the type species there is 

 no slit-band and they put it in the same family as Siuuites [= Brotowartliia'\. 



The type species is B. nana, Meek. 



1. Bucaniella trilobata (Sowerby). Plate V, fig. 12; Plate VI, figs. 1—3. 



1839. Bellerojjhon trilohatus, Sowerby iu Murchisou's Siliiriau System, p. 604, pi. iii, fig. 16. 



1848. Bellerophon trilohatus, Sowerby, Ferussac et D'Orbiguy, Hist. Nat. Cephal., p. 209, pi. vii, 



figs. 24—27 ( ? pi. viii, fig. 16). 

 1852. Bellero2)hon trilohatus, Sowerby, McCoy, Syu. Brit. Palseoz. Foss. Woodw. Mus., fasc. ii, p. 311. 

 ? 1852. Bucania trilohata (Conrad), Hall, Palseoiit. New York, vol. ii, p. 13, pi. iv his. 

 1884. Bellerophon trilohatus, Sowerby, Liudstroiu, Silur. Gastrop. Pterop. Gotland, p. 80, pi. iv, 

 figs. 13—15. 

 ? 1901. Bucania trilohata (Conrad), Grabau, Bull. New York State Mus., no. 45, vol. ix, p. 213, 



fig. 114. 

 ? 1909. Bellerophon trilohatus, Sowerby, Moberg and Griinwall, Oni Fyledalens Gotlandiuni, Kungl. 

 Fysiogr. Stillsk. Handl., vol. xx, no. 1, p. 44, pi. iii, figs. 13, 14. 



1 Koken, op. cit. (1897), p. 137, text-fig. 10. 



3 Perner, op. cit., p. 82, pi. Ixxxix, figs. 9 — 11, text-fig. 56 a, h. 



3 Ibid., p. 85, pi. ixxxviii, figs. 4 — 5, text-figs. 58, 59. 



* Ihid., p. 87, pi. ixxxix, figs. 12, 13, text-fig. 61. 



^ Ihid., p. 84, pi. ixxxvii, figs. 5 — 8, text-fig. 57 a, b. 



6 Meek, ' Proc. Amer. Phil. Soc.,' vol. v (1870), p. 426. 



^ Clarke, " Foss. Devon. Parana" (' Mon. Serv. Geol. Mineral. Brasil,' vol. i, 1913), pp. 168—170. 



8 Koken, ' Die Leitfossilieu ' (1896), p. 100. ^ Ulrich and Scofield, op. cit., p. 848. 



