206 MR F. R. COWPER REED ON 



specimen showing the dorsal face and on several fragments. The dorsal face and shape 

 of the shell resemble the Cambrian species H. signatidus, Novak, * from Stage C, but the 

 longitudinal lineation is different. The ornamentation is more like that found in many 

 species of Orthotheca in Bohemia, figured by Novak, but H. norvegicus, Kjerulf,f 

 from Norway, may be compared with it. The minute cancellation is met with more 

 generally in species of Orthotheca. The shape of the shell resembles the figure of a 

 small unnamed species of Hyolithes from Tyrone, described by Portlock \ as the 

 " internal bone of a Cephalopod." 



Hyolithes columbanus, sp. nov. (PI. I. figs. 14-1 Ad.) 



Shell large, gently curved ventralwards, tapering at about 1 in 4-5, with rather an 

 obtuse blunt tip. Ventral face moderately convex, rounded, not angulated. Lateral 

 angles acute, but not sharp. Dorsal face slightly convex. Mouth with dorsal lip 

 gently arched, not high ; ventral lip straight. Cross-section unequally biconvex. Shell 

 thick, with strong transverse growth-striae and ridges, especially on dorsal face, which 

 also shows near lip about 20 impressed, widely distant, regular longitudinal striae, and 

 a very delicate close longitudinal lineation over the whole surface ; on the ventral face 

 the longitudinal striae are indistinct. 



Dimensions : — 



Length of fragment . . .55 mm. (estimated length of shell 80-90 mm.). 



Width of mouth . . 18 „ 



Horizon and Locality. — Drummuck Group, Thraive Glen. 



Remarks. — This species is not abundant. Its shape, curvature, and cross-section 

 distinguish it from H. asteroideus, and its ornamentation from H. multi'punctatus (q.v.). 

 Eichwald's H. lotus § is allied in curvature, cross-section, and apparently in ornamenta- 

 tion, but tapers much more rapidly to the apex. 



Hyolithes girvanensis, sp. nov. (PI. I. figs. 15-17«.) 



Shell slender, straight, slowly tapering to sharp point at about 1 in 5 or 6. 

 Ventral face angulated in middle, the two sides meeting at about 110°-120°, with 

 narrow, flattened border at sides. Dorsal face flat, or nearly so. Cross-section triangular. 

 Lateral angles acute, sharp. Ventral face with very fine longitudinal striation (rarely 

 visible), and stronger transverse concentric growth-striae. Dorsal face with very slightly 

 arched lip and strong transverse concentric growth-striae. 



Dimensions : — 



Length of shell . . . . . . . 17 - mm. 



Width of shell ....... 3-25 „ 



* Novak, "Rev. Palaeoz. Hyol. Bohm.," Abh. Icon. bohm. Gesell. Wiss., vii., Bd. iv. (Math.-Nat. Kl.), No. 

 (1891), p. 23, t. iv. figs. 37-39. t Holm, op. cit., p. 87, t. iii. figs. 1-5. 



X PoBTLOOK, Geol. Hep. Londond., p. 470, pi. xxix.A. fig. 6. 

 § Eichwald, Leth. Ross., p. 1045, t. xl. fig. 1G. 



