30 ORDOVICUAN AND SILURIAN BELLEROPHONTACEA. 



trilohatus (Sow.) ? var. bisidcatus, Roem., and somewhat superficially discussed the 

 question of its reference to Sowerby's species. But the affinities of the Devonian 

 forms cannot be discussed here. 



Horizons. — (1) Upper LudloAv ; (2) Wenlock Series; (3) Upper Llandovery; 

 (4) Lower Ludlow. 



Localities. — (1) Felindre; Storm Hill, Llandeilo ; Kendal; (2) Dudley; (3) 

 Eastnor Park [28061] ; Tonlegee, Galway ; (4) Freshwater East, Pembrokeshire. 



2. Bucaniella quadrisulcata, sp. nov. Plate VI, figs. 4, 5. 



Specific Gltaracters. — Shell involute, subglobose. Outer whorl nearly com- 

 pletely embracing inner whorls, broader than high, increasing rather rapidly in 

 size towards mouth; dorsum narrowly rounded, strongly convex, separated from 

 lateral portions of whorl by deep revolving groove on each side, and itself divided 

 into three portions by pair of weaker revolving furrows, the median portion of 

 dorsum being the widest ; lateral portions of whorl swollen below outermost 

 revolving grooves. Umbilicus deep, small, situated below centre of shell. 



Dimensions. — Height, 6 mm. ; width of mouth, 5 mm. 



Horizon. — Llandovery Series. 



Localities. — Tlie Frolic, Haverfordwest ; ? Tonlegee, Galway. 



Licniarks. — This shell differs from B. trilobafa (Sow.) by possessing two pairs 

 of revolving grooves, but otherwise it closely resembles that species. Only internal 

 casts are known. There is no trace of a slit-band. In the Jermyn Street Museum 

 one of the specimens labelled 7/. trilohatus, from Tonlegee, Co. Galway, shows 

 similar weak additional revolving grooves. The type-specimens are in the Turnbull 

 Collection in the Sedgwick Museum, and come from the Llandovery of Haver- 

 fordwest. 



Group II. FiSSIDOESATA. 



Genus BUCANIA, Hall (restr.). 



Generic Characters. — Shell involute, composed of few (3 — 5) whorls; umbilicus 

 large, more or less open. Aperture usually transverse, not abruptly expanded ; 

 dorsal sinus broad V-shaped with central slit. Slit-band distinct, raised or 

 depressed. Surface of shell ornamented with equal or unequal revolving lines or 

 riblets crossed by oblique transverse growth-lines parallel with the margin of the 

 aperture, the intersections of the two sets of lines being nearly always rectangular. 



The definition and limitations of this genus as laid down by Ulrich and Scofield^ 

 are here followed. The type is Belleroplion sulcatinus, Emmons,^ of the Chazy 

 Limestone. 



1 Ulrich and Scofield, op. cit., pp. 850, 883—886. 



2 Emmons, ' Geol. Eep., 2nd. Distr., New York,' 1842, p. 312, fig. 4. 



