ANIMALS. 215 



Pleurotomaria. considering that living specimens of a species have been dredged in 

 deep water off Lerwick in Shetland, " adhering to stones like Emarginula^''^ it may be 

 concluded to be a ground-dwelling genus : it consequently differs from Tanthina — by 

 some supposed to be an allied genus — which is essentially an ocean-surface inhabitant. 



No evidence has yet come to light proving that any species are perlaceous, — a 

 circumstance, which, viewed in connexion with the histology of the shell of Pleuroto- 

 maria crispata {Scissurella id., Flem.), is strongly in favour of the genus being essentially 

 non-perlaceous. 



Pleurotomaria appears to have existed from nearly the earliest portion of organic 

 time to the present moment ; but the species have evidently decreased in dimensions, 

 and numerical amount during the Tertiary and existing periods. 



Pleurotomaria antrina, SMotlieim. Plate XVII, figs. 1, 2, 6. 



Trochilites ANTKiNUS, Sclil. Akad. Miiiicb., vol. vi, p. 32, pi. vii, fig. G c (? not a, b), 



1816. 

 (?) Pleurotomaria (?), J. de C. Sow. Sedgwick, Trans, deal. Soc. Lend., 2d series, vol. iii, 



p. 118, 1829. 

 (?) — (?) „ PhilUps, Encyc. Met., vol. iv, p. 618, 1834. 



— ANTEiNA, Schl. Geinitz, Gsea von Sachsen, p. 95, 1843. 



— CAEiNATA, J. Sow. De Verneuil (apud King), Bull. Soc. Geol. de France, 



2™=serie, vol. i, p. 34, 1844. 



— — „ Geol. Russ., vol. i, p. 225, 1845. 



— — „ Tennant, Strat. List, p. 89, 1847. 



— Permiana, Kinff. Catalogue, p. 13, 1848. 



— Sedgwickiana, Eowse. Trans. T. N. F. C, vol. i, p. 238, 1848. 



— — , var. ampulla, Howse. Op. cit. 



— ANTRINA, Schl. Geinitz, Versteinerungen, p. 7, pi. iii, fig- 19 a, b, 1848. 

 (?) — Verneuili, Geinitz. Op. cit., p. 7, pi. iii, figs. 17 a, b, 18 a, b. e, 1848. 



Diagnosis. — "Short: conical. Whorls rounded; marked with distinct, tolerably 

 regular, incremental striae. Fissure-hand broad ; bounded on both sides by a narrow 

 line."2 



" This species resembles the Pleurotomaria carinata of J. Sowerby, with which I 

 formerly identified it ; but it has a concave sinus-band and a small umbilicus : its 

 colouring consists of straight and not zig-zag longitudinal bands, as in the latter : it is 

 spirally threaded, and its pillar-lip is perpendicular."^ The specimen represented by 

 fig. 19, pi. iii, in the 'Versteinerungen,' is more distinctly marked with lines of growth 

 than any that have occurred to me. Occasionally specimens are found with the spire 



^ Vide Jefireys, Annals and Magazine of Natural History, 2d series, vol. iv, p. 300. 



* Vide Geinitz, 'Versteinerungen,' p. 7. "Ein kurz-kegelformiges Gewinde von vier stark gewolbten 

 Umgangen, in deren Mitte eine breite Spaltdecke von zwei schmalen Leisten begranzt wird. Die ganze 

 Schale ist mit deutlichen, ziemlich regelmassigen Zuwachstreifen verziert." 



* King, Catalogue, p. 13. 



