NUCULANA BREVIROSTRIS. 203 



redescribed and figured in vol. ii, ' Geol. Surv. Illinois,' p. 283, pi. xx, figs. 6 a, 6 b. 

 In the absence of American specimens for comparison, I hesitate at present to 

 place this species as a synonym of the species under discussion. 



A series of shells which I refer to this species has been obtained from the 

 shales below the base of the Millstone-grit in tunnelling through Pule Hill, near 

 Marsden, by Messrs. Barnes and Holroyd. I am able to figure a series of these 

 specimens, PI. XV, figs. 44 — 46 ; fig. 46 is a perfectly preserved specimen. At 

 this locality the shell appears to be very rare indeed, probably being confined to a 

 very narrow horizon. 



Nuculana bkevirostris, Phillips, sp., 1836. Plate XV, figs. 26 — 31. 



Nucula brevirostris, Phillips, 1836. Illustr. Geol. Yorkshire, part 2, p. 210. 



pi. v, fig. 11 a. 



— — Morris, 1843. Catal. Brit. Foss., 1st edit., p. 94. 



— M'Cog, 1845. Synops. Carbonif. Foss. Ireland, p. 68. 



— — — — Ibid., p. 70, pi. xi, fig. 19. 



— brevirostra, Brown, 1849. Illust. Foss. Conchology, p. 187 (figure 



wanting). 

 Leda brevirostris, d'Orb., 1850. Prodrome paleontol., p. 130. 

 — cuneata, de Ryckholt, 1851. Melanges paleontol., p. 147, pi. xvii, figs. 



32—35. 

 Non — ? brevirostris, Hall, 1S70. Prelim. Notice Lamellibranehiata, ii, p. 6. 



Nucula Youngi, R. Etheridge, jun., 1876. Ann. Mag. Nat. Hist., ser. iv, vol. 



xviii, p. 104, pi. iv, figs. 11 — 13. 

 Non Leda (Nuculana) brevirostris, Sail, 1883. Pal. New York, vol. v, pt. 1, 



pi. xlvii, figs. 38, 39 (40, 41 ?). 

 — — brevirostris, Hall, 1885. Ibid., vol. v, pt. 1, Lamellibranehiata, ii, p. 329, 



pi. xlvii, figs. 38 — 41. 

 Nucula brevirostris, Etheridge, 1885. British Possils, part 1, Palseoz., p. 287. 



Specific Characters. — Transversely ovate, moderately convex. The anterior 

 end is produced, and the posterior, though narrowed and contracted to form a 

 spur, is still the shorter portion of the shell ; it is encroached upon above by a 

 large escutcheon. The anterior border is elliptically rounded. The ventral and 

 inferior margin is convex in the anterior two thirds, but straight and directed 

 upwards and backwards in the posterior third. The posterior border is blunt, 

 very short and truncated, meeting the upper and lower margins at rounded 

 obtuse angles. The hinge-line is rounded in front, straight behind, the posterior 

 portion being depressed. 



The umbones are obtuse, small, incurved, and contiguous; not marked off in 

 front from the rest of the shell ; encroached upon behind by the escutcheon. 



