LINGULA. 183 



II. Family — Discinimi, Gray, 1848. 

 1. Genus — Discina, Lamarck, 1819. 

 1. Discina nitida, Phillips, sp. Plate XXII, figs. 11, 11 a, 12. 



1836. Oebicula nitida, Phillips. Geo]. Yorks., vol. ii, p. 221, pi. ix, figs. 



10—13. 

 1865. Discina nitida, Davidson. Brit. Foss. Brach., vol. iii, p. 104, pi. xx, 



figs. 9— 10 a. 

 1871. — — ? Kaj/ser. Zeitsch. Deutsch. Geol. Gesell., vol. xxin, 



p. 640. 



Size. — Length 23 mm., width 18 mm. 



Localities. — In the Museum of Practical Geology is a lower valve from 

 Barnstaple, and two upper valves (the smaller of which was figured by Davidson) 

 from West Angle (Pembrokeshire). In Miss Partridge's Collection is a specimen 

 of each valve from Saunton. I have obtained specimens from Saunton Hotel and 

 the " Laticosta Cave," * Baggy. 



Remarks. — The comparison of our specimens with a large series of Carboni- 

 ferous specimens leaves no doubt of their specific identity. The only differences 

 observable are that the Devonian specimens sometimes are slightly larger and 

 sometimes more elongate and oval, and that the foramen of the lower valve, as 

 seen internally in them, is much smaller than it is as seen externally in the 

 Carboniferous examples, which difference probably is simply due to its character. 



In Miss Partridge's specimen of the upper valve, the strong median longitu- 

 dinal thickening under the apex is more evident than it is in the Yorkshire shells, 

 in several of which, however, it is observable. 



III. Family — Lingulil\e, King, 1850. 

 1. Genus — Lingula, Bruguiere, 1792. 

 1. Lingula squamifoemis, Phillips. Plate XXII, fig. 13. 



1836. Lingula squamifokmis, Phillips. Geol. Yorks., vol. ii, p. 221, pi. xi, 



fig. 14. 

 1865. — — Davidson. Brit. Foss. Brach., vol. iii, p. 105, 



pi. xx, figs. 11, 12. 



' " Laticosta Cave " is, of course, not a local name in ordinary use. It is as well to remark again 

 that I have simply used it as an abbreviation to indicate the one spot where (in company with 

 numerous other species) Rh. laticosta has hitherto been found. 



