86 MB. H. WOODS ON THE MOLLTJSCA [Feb. 1 896,. 



Family Pleurotomariidse, d'Orbigny. 



Genus Pleurotomakia, Defrance, 1821. 



Sub-genus Leptomaeia, Eudes-Deslongchamps, 1865. 



Pleueotomaeia (Leptomaeia) peespectiva (Mantell). (PI. III. 

 figs. 13, 14, <fc PI. IY. fig. 1.) 



1822. Cirrus perspective, G. A. Mantell, ' Foss. S. Downs,' p. 194, pi. xviii.- 

 f. 12, 21 ; 1823. J. Sowerby, ' Min. Conch.' vol. v. p. 35, pi. ccccxxviii. f. 1, 2. 



1822. Troehus linearis, Mantell, ibid. p. 110, pi. xviii. f. 16, 17. 



1822. Cirrus depressus, Mantell, ibid. p. 195, pi. xviii. f. 18, 22 ; 1823. Sowerby, 

 ' Min. Conch.' vol. v. p. 35, pi. ccccxxviii. f. 3. 



1835. Pleurotomaria distincta?, F. Dujardin, Mem. Soc. geol. de France, vol. ii. 

 p. 231, pi. xvii. f. 6 ; 1840. A. Goldfuss, ' Petref. Germ.' pt. 3, p. 75, pi. clxxxvii. f. 1 ; 

 1841. F. A. Komer, ' Die Verstein. des norddentsch. Kreidegeb.' p. 82 (partim). 



1840. Troehus linearis, H. B. Geinitz, ' Char. d. Schicht. u. Petref. des sachs. 

 Kreidegeb.' Heft 2, p. 46, pi. xiii. f. 6, 8, pi. xv. f. 18, 19. 



1840. Pleurotomaria velata, A. Goldfuss, ' Petref. Germ.' p. 76, pi. clxxxvii. f. 2. 



1840. Pleurotomaria granulifera, Goldfuss, ibid. p. 76, pi. clxxxvii. f. 3. 



1842. Pleurotomaria perspectiva, A. d'Orbigny, ' Pal. Franc. Terr. Cret.' vol. ii.- 

 p. 255, pi. exevi. f. 1-5 ; 1850. J. de C. Sowerby, in F. Dixon's 'Geol. Sussex,' p. 349 

 (p. 384, ed. 2), pi. xxvii. f. 27 ; 1854. J. Moms, ' Cat. Brit. Foss.' ed. 2, p. 271 ; 1863. 

 F. J. Pictet and G. Campiche, ' Foss. Terr. Cret. Ste.-Croix,' ser. 3, pt. ii., Pal. Suisse, 

 p. 454 ; 1874. H. B. Geinitz, ' Das Elbthalgeb. in Sachsen ' (Palaeontographica, 

 vol. xx.), part ii. p. 166 (? pi. xxix. f. 11) ; 1889. A. Fritsch, ' Stud, im Geb. der bohm.. 

 Kreidef. IV. Die Teplitzer Schichten,' p. 74, f.49. 



1845. Pleurotomaria linearis, A. E. Reuss, 'Die Verstein. bohm. Kreideformat.' 

 p. 47 ; 1850. H. B. Geinitz, ' Das Quadersandst. oder Kreidegeb. in Deutschland,' 

 p. 134 (partim) ; 1870. F. A. Bomer, ' Geol. von Oberschlesien,' p. 318, pi. xxxv. f. 1,. 

 2 ; 1874. H. B. Geinitz, ' Das Elbthalgeb. in Sachsen ' (Palaeontographica, vol. xx.) r 

 pt. ii. p. 165, pi. xxix. f. 10 ; 1883. A. Fritsch, ' Stud, im Gebiete der bohm. Kreide- 

 format. III. Die Iserschichten,' p. 95, f. 57 ; 1889. Fritsch, ibid. ' IV. Die Teplitzer 

 Schichten,' p. 74, f. 48. 



1846. Pleurotomaria (Troehus) linearis, H. B. Geinitz, ' Grundriss der Verstein/' 

 p. 355, pi. xv. f. 1. 



Description. — Shell heliciform, depressed, composed of 7 whorls r 

 which are obtusely angular, the parts above and below the angle 

 being flat or nearly flat. Base of last whorl rounded. Sinus-band 

 narrow, prominent, smooth (apparently), placed at the angle, 

 slightly posterior to the middle of the whorl. Umbilicus large,. 

 deep. Sutures shallow. Ornamentation consisting of numerous 

 longitudinal ribs, which, on the earlier whorls, are markedly 

 granular, the granules having a transverse arrangement also.. 

 Growth-lines curving backwards to the sinus-band are seen on 

 some of the later whorls. Base with numerous close-set longi- 

 tudinal (spiral) ribs. Aperture broad, outer lip rounded. Size of 

 a large specimen : length 44 mm., width 82 mm. 



Remarks. — The appearance of this species varies considerably,, 

 according to the state of preservation and the age of the specimens.. 

 The granular character of the ornamentation is seen best in young 

 individuals ; on the later whorls of large specimens the ribs are 

 often nearly smooth, but this is probably due to abrasion. When 

 the shell is much worn, the surface appears to be striated rather 

 than ribbed. The sides of the spire are convex, except in young, 



