Yol. 65.] THE GENU'S LOXOKEMA. 217 



example (No. 21074), is associated with it. There is also a well- 

 preserved specimen (G 32954) in the British Museum (Natural 

 History). L. cornubicdm may be distinguished from the Silurian 

 L. sinuosum (Sow.), with which Phillips confounded it, by the 

 whorls being higher, natter, and more adpressed at the sutui'e, 

 and by the lines of growth forming strong raised threads, 

 and not being so sharply bent. A. d'Orbigny called this species 

 L. phillipsii, but the name cannot stand, as it had previously been 

 used to designate another gasteropod by Ecemer. M'Coy l considers 

 the larger specimen figured by Sowerby 2 as Tetehra nexilis to be 

 identical with this species. It differs, however, by being more 

 slender and by the lines of growth being less curved. 



Dimensions. — The holotype (PI. X, figs. 2 a & 2 6) consists of 

 only three and a half whorls, as the apex is broken ; its length 

 = 31*5 millimetres, and its width = 16"5 mm. 



Locality. — South Petherwin (Cornwall). 



Horizon. — Middle Devonian. 



Loxonema inttjmescens (?) Lindstr. (PI. X, fig. 3.) 



Loxonema intumescens, G. Lindstrom, 1884, ' Silur. Gastrop. & Pterop. Gotland 

 Kongl. Svensk. Vet.-Akad. Handl. n. s. vol. xix, no. 6, p. 143 & pi. xv, fig. 6. 



Diagnosis. — Shell composed of more than nine gradually in- 

 creasing whorls. Whorls flattened above, convex below, having 

 a high-shouldered appearance. Lines of growth forming sharp 

 raised threads, varying in strength, some being stronger than others 

 at irregular intervals, curving very obliquely backward above and 

 forward below, making an almost right-angled sinus slightly above 

 the middle of the whorl. Aperture unknown. 



Eemarks and resemblances. — Through the kindness of 

 Prof. Holm I have been enabled to compare Lindstrom's holotype 

 with a specimen (G 15699) in the Piper Collection in the British 

 Museum (Natural History). This latter shell is so embedded in 

 the matrix that portions of only four whorls are visible, and it is 

 much crushed. Despite its imperfect state of preservation, I think 

 that it is probably identical with the Gothlandic species. The whorls 

 of both have a high-shouldered appearance, and the lines of growth 

 are similar ; the chief distinction lies in the whorls of the British 

 specimen being broader, but this seems to have arisen from pressure. 

 The whorls do not appear to be adpressed at the suture, either in 

 the British or in the Gothlandic specimens ; but none are well 

 preserved, and therefore we cannot be certain of the absence of 

 this feature. This species differs from Loxonema sinuosum (Sow.) 

 in the form of the whorls, which are more prominently convex, 

 and in the sinus being situated higher. Dr. Perner considers 

 L. inexpectatuni, Barr., 3 somewhat like L. intumescens, Lindstr., 

 but the form of the whorls is different. The contour of the 



1 'Brit. Pal. Foss.' 1855, p. 399. 



2 Trans. Geol. Soc. ser. 2, vol. v, pt. iii (1840) pi. liv, fig. 17 & p. 703*. 



3 ' Syst. Sil. Centre Boheme ' pt. i, vol. iv, Gasteropodes, par J. Perner, 

 tomes i & ii (1903 & 1907) p. 330 & pi. lx, fig. 13. 



