44 DEVONIAN FAUNA. 



BemarJcs. — This beautiful species is well described and represented by Phillips 

 in the ' Pal. Foss.,' but it appears to be distinct from the Yorkshire L. rugiferum 

 (Ph.),^ with which he identifies it. It is distinguished by the fact that the ribs are 

 continuous over the whole surface in the adult shell, as well as in the young form. 

 This distinction is observable even in Phillips's own descriptions of his two shells. 

 The evanescence of the upper part of the ribs in adult shells in the Carboniferous 

 species is still more clearly seen in de Koninck's figures,^ who separates the 

 .Devonian form from it on the authority of d'Orbigny under the name of 

 L. anglicum. On the other hand, in all the Devonshire specimens of L. anglicum, 

 even in the largest which I have seen, the continuity of the ribs is clear ; and 

 these ribs also seem slighter, more continuously uniform in size, and rather more 

 flexuous. The same characters are shown by both Clarke's and Trenkner's figures 

 of the German Devonian shell. 



At the same time the two forms have many characters in common, and it is 

 quite possible that the examination of a larger series of examples than we have at 

 present might break down the line of distinction between them. 



Affinities. — L. angulosum, F. A, Romer,^ is a shorter, fewer-whorled shell, with 

 more arching ribs. 



Holopella moniliformis^ F. A. Romer,* differs in having its ribs twice as 

 numerous, and twice as fine. 



II. Family — Naticid^, Forbes, 1838. 



1. Genus— 'Naticofsis, M'Cot/, 1844. 



1. Naticopsis Hallii, n. sp. Plate V, figs. 11, 12, 13? 



Description. — Shell rather small, subglobose, rather oblique. Spire low. 

 turbiniform, consisting of between three and four rapidly increasing convex 

 volutions, which are less than half exposed. Sutures shallow, obtuse. Body- 

 whorl more than two-thirds the total height of shell, voluminous, convex. Mouth 

 pear-shaped, longer than wide, entire, acute behind. Inner lip sigmoidal, 

 somewhat produced below, where it forms a spurious columella, and covered with 

 a spreading callosity. Umbilicus apparently closed. Surface smooth. 



1 1S3S, " Melania rugiferay Phillips, ' Geol. Torks.,' vol. ii, p. 229, pi. xvi, fig. 20. 



2 1881, de Koninck, ' Ann. Musee Eoy. d'Hist. Nat. Belg.,' vol. vi, p. 59, pi. vi, figs. 12, 13. 

 8 18.50, F. A. Romer, ' Beitr. Harzgeb.,' pt. 1, p. 3, pi. i, fig. 5. 



* 186G, ibid., pt. v, p. 8, pi. xxxiv, figs. 5ffl, h. 



