Vol. 52.] OF THE CHALK KOCK. 91 



Family Naticidse, Guilding. 

 Genus Natica, Adanson, 1757. 

 Natica (Naticina *) vulgaeis, Reuss. 



1840. Littorina rotundata, H. B. Geinitz (non Sowerbysp.), 'Char, der Schichten 

 und Petrefacten des sachs. Kreidegeb.' Heft 2, p. 45, pi. xiii. f. 7, pi. xv. f. 16 

 (?pl. xiv. f. 10, pi. xv. f. 17). 



1844. Natica vulgaris, A. E. Reuss, 'Die Kreidegeb. des westlichen Bohmens,' 

 vol. ii. p. 209 ; ? 1843. H. B. Geinitz, ' Die Verstein. von Kieslingswalda,' p. 10, pi. i. 

 f. 21 {non figs. 22-23) ; 1845. A. E. Reuss, ' Die Verstein. der bohm. Kreideformat.' 

 p. 50, pi. x. f. 22 ; 1846. H. B. Geinitz, ' Grundriss der Verstein.' p. 339, pi. xv. f. 18 ; 

 1850. id. ' Das Quadersandst. oder Kreidegeb. in Deutscbland,' p. 128 (partim) ; 

 1889. A. Fritscb, ' Stud, im Geb. der bohm. Kreidef. IV. Die Teplitzer Schichten,' 

 p. 73; 1893. Fritsch, ibid. ' V. Die Priesener Schichten,' p. 82, fig. 67. 



1875. Natica lamellosa, H. B. Geinitz, ' Das Elbthalgebirge in Sachsen' (Palaeonto- 

 graphica, vol. xx.), pt. i. p. 243, pi. liv. f. 17 ; 1877. A. Fritsch, ' Stud, im Gebiete 

 der bohm. Kreideformat. II. Die Weissenberger und Malnitzer Schichten,' p. 105, 

 woodcut 43 ; 1883. Fritsch, ibid. ' III. Die Iserschichten,' p. 94. 



Description. — Shell a little longer than wide. Spire more than 

 half the last whorl in length. Whorls 5, rounded and very convex, 

 especially the last. Surface with lines of growth and also distant 

 faintly-marked rings (varices) ; the lines of growth are crossed by 

 fine longitudinal striae. Umbilicus rather small. Aperture elongate- 

 oval. 



Affinities. — Geinitz considers this species to be identical with N. 

 lamellosa, of Romer, 2 from Kieslingswalda ; but Fritsch apparently 

 regards it as distinct. This, however, is a point which can hardly 

 be settled by the aid of Romer's figure. 



N. cretacea, Goldf uss, 3 from the Aachen Greensand, diners from 

 iV. vulgaris in having a much wider aperture. 



If. exaltata, Goldfuss, 4 also from the Aachen Greensand, is dis- 

 tinguished by the greater length of the shell. 



N. lyrata, Sowerby, 5 from Gosau, is allied to N.. vulgaris, but 

 possesses a shorter spire. 



Stoliczka 6 considers that Euspira pagoda (Forbes), from the 

 Arrialoor Group, is closely related to this species, but the whorls in 

 that form are more numerous and the spire more acute. 



Remarks. — 1 have seen 23 examples of this species from the 

 Chalk Rock, but most of them are in the condition of casts ; a few 

 show portions of the shell with the lines of growth and longitudinal 

 strise. The varices are indicated on the casts by slight depressions. 



The type figured by Eeuss came from the Planer-Mergel of 

 Priesen, Bohemia. 



1 Naticina of Guilding, 1834. 



2 ' Die Verstein. des norddeutsch. Kreidegeb.' (1841) p. 83, pi. xii. f. 13. 



3 ' Petref. Germ.' (1840) p. 119, pi. cxcix. f. 12. See also Binkhorst, 'Mon. 

 des Gast. et Ceph. de la Craie Super, du Limbourg ' (1861), p. 21. 



4 Ibid. (1840) p. Ill, pi. cxcix. f. 12. 



5 Sowerby, Trans. Geol. Soc. ser. 2, vol. iii. (1835) pi. xxxviii. f. 11. See 

 also d'Orbigny, ' Terr. CreV vol. ii. (1842) p. 161, pi. clxxii. f. 5 ; Zekeli, ' Die 

 Gastr. d. Gosaugeb.' Abb. d. k. k. geol. Beichsanst. vol. i. (1852) p. 46, pi. viii. 

 f. 5; and Stoliczka, ' Cret. Fauna S. India/ vol. ii. (1868) p. 303, pi. xxii. f. 2 

 (Palaeont. Indica). . 6 Qp. cit. p. 301. 



