48 
DEVONIAN FAUNA. 
3. Myalina stulta, Whidborne, sp. PI. Ill, fig. 8. 
1889. Mytilus stultus, Whidborne. G-eol. Mag., dec. 3, vol. vi, p. 79. 
Description. — Right valve rather higher than long, nearly semicircular, very 
convex. Umbo rather large, recurved, compressed, proximate, situate at the 
anterior extremity of the upper margin. Hinge-margin straight, almost as long 
as the shell. Front margin very broad, straight. Inferior and posterior margins 
regularly convex. Hind wing rather large, indistinct, and concave. Line of 
greatest elevation close to and parallel with the front margin ; the surface being 
very convex over it, becoming gradually less convex in rear of it, and sinking 
almost perpendicularly to the margin in front of it. Surface covered with 
numerous close, elevated, regular, transverse threads, and two or three stronger 
growth-lines. 
Size. — Length 22 mm., breadth 18 mm., depth of single valve 8 mm. 
Locality. — There is a single specimen from Wolborough in the Museum of 
Practical Geology. 
Bemarhs. — This fossil is distinguished from the species that accompany it by 
its short, almost semicircular shape, its great convexity, and its strong, numerous, 
and regular surface-markings. It is in a rather poor state of preservation, its 
shape being obscured by rock, and its surface granulated by the coarseness of the 
matrix, besides being decorticated in the manner characteristic at Wolborough. 
It is possible that it bore radiating as well as transverse threads, but it is difl&cult 
to say how far these marks are natural or due merely to fossilization. 
Affinities. — Two poor specimens of Myalina ornata^ in the British Museum, 
from Winterberg, seem very similar in shape and ornament, but judging from 
Romer's description that species was much higher and sharper above. 
From Myalina egregia it differs in its much greater convexity, its narrower and 
more concave hind wing, and in other particulars. 
Modiola amygdalina, Phillips,^ is more coarsely ribbed and less abruptly 
truncated on the anterior side. 
4. Myalina luna, n. sp. PI. IV, fig. 1. 
Description.— LqH valve long, lunate, flattish. Umbo very small, depressed, 
situate at the anterior point of the hinge-margin, bent forward. Hinge long, 
1 1860, r. A. Eomer, ' Beitr.,' pt. 4, p. 162, pi. x.xv, figs. 12 a, h. 
2 1841, Phillips, ' Pal. Foss.,' p. 38, pi. xvii, figs. 62 a—c. 
