﻿188 DEVONIAN FAUNA. 



Turbo ccelatus, Goldf., 1 is more globular, has a flat band following the suture, 

 which makes the mouth more square above, and its ornament is uniform. 



2. Littorina TJssheei, n. sp. PI. XIX, figs. 6 — 8. 



Description. — Shell rather small, short, globose, oblique, smooth. Suture simple, 

 obtuse, shallow. Spire short, obtuse, convex, of about four narrow, little exposed, 

 and rapidly increasing whorls. Apex acuminate. Whorls rather broad, convex, 

 rather flatter on the back, gently and obliquely rounding in to the base. Mouth 

 entire, continuous, oblique, pear-shaped, rather elongate, pointed above, roundly 

 convex and rather produced below. Outer lip moderately convex. Inner lip nearly 

 straight, thick, diffuse, flattened, spreading over and partially or wholly covering 

 the umbilicus with a callosity, bearing a broad, low, flat, very indistinct tooth in 

 the centre of the aperture, in front of which it trends in an oblique curve round 

 the front of the mouth, and has along its centre a distinct, shallow, rounded groove. 

 Surface covered with multitudinous, indistinct, microscopical, transverse striae or 

 growth-lines, so fine that the shell appears smooth to the naked eye. Shell- 

 structure thick. 



Size. — Height 13 mm., width about 11 mm. 



Localities. — There is a large specimen in my Collection from Lummaton, and 

 four small specimens in Mr. Vicary's Collection from Chudleigh. 



Remarks. — It is with some doubt that I place these specimens together, as 

 they present some differences, and it is possible that better specimens may prove 

 them to belong to two distinct though closely allied species. My specimen, which 

 wants is much the spire, the largest shell ; it shows the low tooth on the inner lip, 

 and the covered umbilicus ; and the front part of the inner lip seems perhaps 

 shorter and less distinctly grooved than it is in Mr. Vicary's fossils. In these latter 

 the lip shows hardly any trace of a tooth, and its callosity is less defined and 

 extends further over the base of the shell. It is, however, possible that these 

 differences may be due to age or contortion from which the Chudleigh specimens 

 have considerably suffered, and at all events the material at hand is quite 

 insufficient to show them to be distinct. 



Affinities. — From Naticopsis primigenia, Eichwald, 2 this species differs in being 

 more oblique, and in having a stouter shell, a smaller and less circular mouth, a 

 spreading inner lip, and a longitudinal groove. 



From Plagiothyra archon, mihi, it differs by being of a more globose form, 

 with a smaller spire and a much more elongate and differently formed mouth. 



1 1844, Goldf., ' Petrel,' vol. iii, p. 90, pi. cxcii, figs. 3 a— c. 



2 Eichwald, ' Leth. Eoss.,' p. 1106, pi. xliv, figs. 6 a, b. 



