102 DEVONIAN FAUNA. 
3. Genus.—Biripa, Davidson, 1882. 
1. Bretpa Honti, Davidson. 
1882. Birrpa Hun, Davidson. Brit. Foss. Brach., vol. v, pt. 1, p. 28, pl. i, 
figs. 17—18. 
Locality.x— About eighteen specimens are in my Collection and one in the 
Woodwardian Museum from Lummaton. 
Remarks.—This small but very distinct little species is not very rare, but 
from its small size and great fragility it is easily lost or overlooked. 
It is interesting to note that the Barton specimen in Mr. Lee’s Collection, 
originally described by Davidson as A. lepida, is really a very poor specimen of the 
present shell. Davidson’s figure and description, however, were evidently com- 
pleted from more perfect German specimens, and therefore still apply to B. lepida ; 
and, while that species must be consequently removed from the list of Lummaton 
fossils, it remains a British species, as it occurs in abundance and beautiful 
preservation at Hope’s Nose. 
Affinities.—Terebratula venusta, Schnur,’ seems rather similar, but is a larger 
shell with more numerous and less distinct ribs. 
2. Birrpa PpuaNna, n. sp. PI. XII, figs. 8, 8a, 8b. 
Description.—Shell very small, flat, circular. Ventral valve slightly more 
convex than the other. Beak erect, not recurved, small, prominent, with straight 
lateral margins. Area triangular, flat. Foramen apparently apical, rather large, 
and separated from the hinge by a high deltidium. Hinge-margin moderately 
convex. 
Dorsal valve nearly flat, with a broad shallow depression in the centre, which 
is most visible near the beak. Front margin slightly invading that of the ventral 
valve, so that the valves meet in a shallow inverted arch. 
Size.—Length 7 mm., width 10 mm., depth 2°5 mm. 
Localities —There are four specimens in my Collection from Lummaton. 
Remarks.—These are very minute shells, and may possibly prove to be only 
the young of some other species. At the same time they appear to have several 
characters which are so different from those of the accompanying species that, in 
1 1854, Schnur, ‘ Paleontographica,’ vol. iii, p. 180, pl. xxiv, figs. 3a, 0b. 
