38 ORDOVICIAN AND SILURIAN BELLEROPHONTACEA. 



embrace one another for about half their height. Outer whorl transverse, more 

 than twice as wide as high, with more or less flattened broad dorsum, increasing 

 rather rapidly in size to the mouth ; umbilical edges subangular, situated a little 

 below middle of whorl ; umbilical slope steep. Slit-band narrow, slightly elevated, 

 with sharp narrow edges. Surface of dorsum with 8 — 10 thick, low, rounded, 

 equal revolving lines on each side and G — 8 on umbilical slope, becoming rather 

 further apart laterally. Transverse sti'ige indistinct. 



Dimensioits. — Height of shell, about 21 mm. ; width at mouth, about 18 mm. 



Horizon. — Lower Ordovician : Balclatchie Group (Conglomerate). 



LocaJitij. — Balclatchie, near Girvan. 



_Be)W(ty7iS.— This species exposes the inner whorls more than any of the others 

 from Girvan, ))ut it is allied to K. niclioJsonl and K. J'uiijmdis var. (jirnanensls in most 

 respects. The wider and more open umbilicus and the sharper angulated umbilical 

 edge in th& adult are distinguishing marks. Owing to the state of preservation the 

 transverse stri{3e are not clearly visible, but the revolving lines seem so close 

 together as to leave little rooui for them in the interspaces. The types occur 

 in Mrs. Gray's Collection, and the species is dedicated to the Scottish geologist, 

 James MacCuUoch. 



7. Kokenospira muUochensis, sp. nov. Plate VIII, figs. 1, 2. 



Specific Glmracters. — Shell subglobose, of o transverse rouuded whorls. Umbilicus 

 deep, small, about one-fourth the diameter of the shell. Outer whorl rather rapidly 

 increasing in size and embracing three-fourths of preceding whorl, wider than 

 high, with broad convex dorsum and rounded umbilical edge. Slit-l>and narrow, 

 not elevated. Mouth slightly expanded at base, wider than high, with broad, 

 shallow, V-shaped sinus in outer lip. Surface of whorl ornamented with closely 

 placed, low, thick, rounded revolving spiral lines parallel to the slit-band, 12 — 14 

 on each side of it on dorsum, crossed by obliquely transverse delicate striae meeting 

 slit-band at -15°— 60°. 



Dimensions. — i ii 



Heig^ht of shell . . . about 14 mm. . 28 mm. 



Width of mouth . . . „ 16 „ . 32 „ 



Horizon. — Lower Llandovery : Mulloch Hill Group. 



Locality. — Mulloch Hill, near Girvan. 



Remarks. — The dorsum is more convex, the umbilicus smaller, the slit-band 

 narrower, and the revolving lines thicker and closer than in K. linguaMs var. 

 girvanensis. The interspaces are also nuich narrower on the dorsum than in that 

 species, and the revolving lines seem to be equal and equally spaced, with the 

 transverse lines crossing them, thus producing a marked cancellation. As in the case 



