88 DEVONIAN FAUNA. 



Size. — Height 8 mm., length 22 mm., depth of one valve 2 mm. 

 (approximately) . 



Locality. — There are several small specimens in the Barnstaple Atheugeum 

 from Kingdon's, Shirwell, and two or three in the Porter Collection from Pilton. 



Bemarlcs. — While in many respects good, the specimens leave much that is 

 doubtful about this species. It seems to be distinguished by its very long subquad- 

 rate or rhomboidal shape and slightly sigmoid inferior margin. 



3. Peothyeis scalpeata, n. sp. Plate IX, figs. 17, 18, 18 a; and (?) Plate X, 



figs. 16— 17 a. 



Bescriijtion. — Shell small, equivalve, gently convex, lancet-shaped, very 

 transverse. Umbo wide, low, proximate, slightly rounded, very oblique, arching 

 forward, concavely truncate in front. Anterior margin produced, broad, very 

 convex, but suddenly and deeply notched at the medio-anterior point, below which 

 it immediately curves with a slight convexity into the inferior margin. Inferior 

 margin very long, and gently and evenly convex. Posterior side long and narrow. 

 Posterior margin produced to an almost sharp median angle, with similar gently 

 convex sides ; the upper side becoming slightly concave as it meets the end of the 

 hinge-margin rather behind the middle line of the shell. Hinge-margin straight, 

 about half the length of the shell. Hinge with three or four long, linear, parallel 

 (or radiating), transverse, posterior lateral teeth. Lunule deep, ovate, defined by 

 a raised tubular ridge, which arches from the umbo to the notch in the anterior 

 margin. Contour of back vertically gently convex, horizontally nearly flat, 

 obliquely truncated in the extreme suj^ero-posterior part, concave in the antero- 

 superior part or lunule, and broken by the squarish conical arching ridge running 

 from the front of the umbo to the anterior notch. Surface ornamented with 

 distant impressed strige or growth-lines, especially near the margins, and with two 

 or three slight sunken radiating threads on the postero-superior part of the shell. 



Size. — Length 16 mm., height 7 mm., depth 3 mm. 



Localities. — There is a specimen (of the open valves) from Croyde, and another 

 from the Sloly beds of Plaistow Mill Quarry, near Barnstaple, in the Museum of 

 Practical Geology ; there are numerous specimens from Sloly in the Barnstaple 

 Athengeum, from S.W. of Sloly in the Woodwardian Museum, and from the Sloly 

 Quarry in my Collection. 



Remarks. — This species, though rarely found in at all good preservation, is 

 evidently an abundant and characteristic fossil of the Sloly beds. In the Sloly 

 Quarry Dr. Hicks and I observed a bed near the Lingula squamiforwis bed which 



