BUCANIOPSIS NICOLI. 61 



Ulrich, 1 and to a less extent B. calypso, Pernery while B. eiseni (Lindstrom) 3 may 

 also be compared. 



3. Bucaniopsis nicoli, sp. nov. Plate X, tigs. 7 — 9. 



Specific Characters. — Shell high, of few whorls rapidly increasing in size, much 

 expanded at month. Umbilicus small, deep, about one-fifth or one-sixth the height 

 of shell. Outer whorl wider than high, rapidly increasing in size near mouth ; 

 dorsum rounded, convex in early part of whorl, but becoming decidedly carinate 

 towards month, bearing narrow slightly elevated slit-band with a narrow groove 

 along each side of it; umbilical edges subangular; umbilical slope short, steep. 

 Mouth very large with broad open V-shaped sinns in outer lip ; large rounded 

 prominent apertural lobes expanded ;it right angles to plane of shell, and large 

 strongly deflected inner lip reaching nearly to base of shell. Surface of shell 

 finely cancellated by numerous regular closely-placed thread-like revolving lines of 

 subequal size parallel to slit-band, becoming slightly sinuous and divergent on 

 apertural lobes, crossed by much more delicate transverse arched stria? meeting slit- 

 band at 00° — 75°. Strong growth-line and ridges concentric to margin in peristome. 



Dimensions. — Height of shell, 18 mm.; height of mouth, 13 mm.; width of 

 mouth, 19 mm. 



Horizons. — (1) Drummuck Group (Starfish Bed) (Upper Ordovician); (2) Bala 

 Series. 



Localities. — (1) Thraive Glen; Drummuck, Girvan ; (2) Onny River, 

 Shropshire. 



Remarks. — This shell is much like the imperfectly known B. forbesi from 

 Shalloch Mill, but the month seems larger and the whole shell broader, and it 

 more resembles the Silurian B. expansus. 



There is one specimen [28012] in the Jermyn Street Museum from the Bala 

 beds of the Onny River, Shropshire, which seems inseparable from the Girvan 

 form above described. It shows the dorsal aspect and the outline of the mouth 

 and has the ornamentation beautifully preserved. The revolving lines show a 

 tendency to be alternately thick and fine, but perhaps this feature may be 

 sufficient to regard the shell as marking a variety. The dimensions of the specimen 

 are as follows : Height of shell, I'd mm. ; width of month, 17 mm. 



-i. Bucaniopsis ? cf. latevittatus (Lindstrom). 



Some internal casts of a Bellerojphon in the Sedgwick Museum from the 

 Wenlock Limestone of Dudley belong to a very broad low globose shell with 



1 Ulrich and Scofield, op. cit., p. 925, pi. lxii, figs. 56 — 61. 



2 Perner, op. cit , \>. 157, text-fig. 110a — c. 



3 Lindstrom, op. cit., p. 78, pi. vi, figs. 19 — 21. 



