CAMAROPHORIA. 137 
1879. RHYNCHONELLA MATERCULA, Barrande. Syst. Sil. Bohéme, vol. v, pl. xxxiv, 
figs, 5—14; pl. exiil, fig. 2, 1-22; 
and pl. exxxyv, fig. 5, Bt. F. 
1879. — PALUMBINA, Barrande. Ibid., pl. exiii, fig. 8, 1—11, Et. FB. 
1884, —_— protracta, Clarke. Neues Jahrb. f. Min., Beil.-Band iu, 
p: 386. 
1885. — SUBCUBOIDES, Maurer. Abhandl. Grossh. Hessisch. Geol. 
Landes., vol. i, pt. 2, p. 200, 
pl. viii, figs. 26—28. 
1889. — cuBorpES ?, Toll. Mém. Acad. Sci. St. Petersbourg, ser. 7, 
vol. xxxvii, No. 3, p. 22, pl. ii, figs. 
lla, d, o. 
Description.—Shell small, sub-globose, sub-pentagonal, generally nearly as long 
as wide. Umbo small, sharp, slightly curved. Dorsal valve convex above, 
straight below; mesial fold flat, elevated, with steep sides; sides of the valve 
rather dilate. Ventral valve flat, narrow, with a rather abrupt sinus below, its 
lateral margins sigmoid and its front margin much elevated and forming a 
rectangle. Deltidium apparently wide; foramen minute and situate immediately 
under the point of the beak, at a distance from the dorsal valve. Ribs rounded, 
close, rather low, numerous, not reaching to the umbones, four or five on the fold 
and eight or ten on each side, not grooved near the margins. Margins thickened 
and duplicated in old shells ; sometimes having fringes or expansions. 
Size.—Length, 15 mm.; width, 15 mm.; depth, 10 mm. 
Localities—I have about twenty-eight specimens from Lummaton, and there 
is one from Wolborough in the Museum of Practical Geology. 
Remarks.—These small shells at first sight seem like young specimens of 
Rh. cuboides, and as such I presume they have been hitherto regarded. They, 
however, may be distinguished from that species by several characters. Thus 
the beak is rather higher, the angle of its sides is less obtuse, the fold is much 
narrower and more pronounced, and bears much fewer ribs, the shape is more 
pentagonal, the centre of the front margin is lower, and the ribs never have 
a central groove. In general appearance it comes midway between Lh. cuboides 
and Rh. parallelepipeda. That it is not a young form is proved by the 
character of its margins, the duplication of which is never seen in the two 
last-mentioned species. It appears exactly to agree with the figures of 
Rh. subcuboides, Giebel, given by himself and by Maurer; with those given by 
Kayser it is not quite so similar, as the sides of the beak in them are straighter 
and broader. It is evidently the same as Steininger’s 1’. ascendens. 
Affinities—It approaches very near to Rh. microrhyncha, F. Romer,’ as given 
1 1844, F. Romer, ‘Rhein. Uebergangsgeb.,’ p. 65, pl. v, figs. 2a—e. 
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