92 DEVONIAN FAUNA. 
Remarks.—Innumerable specimens of small Terebratuloid shells occur at 
Lummaton. The preparations of the loop made by Mr. Norman Glass from 
specimens selected by Mr. Davidson and myself have proved conclusively that these 
belong to several distinct and in some cases remote species. With this help it has 
become, in many instances, easy to recognise them by their external characters, 
but very often, especially in the case of badly preserved or of young specimens, it 
is still almost impossible to discriminate them with certainty. 
Magellania Whidbornei seems to be one of the rarer species. I have found 
few specimens which seem undoubtedly identical with the shell figured by 
Davidson as the type of his restricted species, while most of the fossils figured in 
his earlier work as Terebratula sacculus are probably specimens of C. virgo, 
Phillips, sp., or other shells. 
Of the shells distinguished by Phillips as T. sacculus, T. virgo, and T. hastata, 
both the former are probable specimens of Centronella virgo, while the latter, 
which is in the British Museum, is a specimen of Merista plebeia. 
In outward characters the present species is distinguishable from smooth and 
worn specimens of C. virgo by its blunter, broader beak, its more rounded anterior 
margin, and its sharper and generally more numerous growth-ridges, which are 
sometimes seen not only near the margins but over the whole shell. Specimens of 
C. virgo can, moreover, be at once identified if their characteristic arching rows 
of prominent punctations are well preserved. 
Glassia Whidbornei, Davidson, is more difficult to distinguish. It seems a 
smaller shell, its beak is somewhat narrower, its foramen is higher, and its surface 
shows no punctations. While, however, full-grown specimens are distinguishable, 
it seems almost impossible to be certain in the case of younger shells, unless the 
surface is in a better state of preservation than my specimens usually are. 
2. Macennanta, ? sp. PI. XI, figs. 2-2. 
Description.—Shell small, flattish, subpentagonal, elongate. Beak large, high, 
wide, not much incurved. Area wide, flat, nearly straight. Deltidium large, 
convex, triangular. Foramen small, circular, immediately under the beak, and very 
distant from the apex of the dorsal valve. Valves equally convex and meeting at 
a very small angle. Front margin flat and straight. Surface very minutely and 
closely punctate, smooth in the centre, and bearing on the marginal third a few 
very low, rounded, indistinct ribs. 
Size.—Length 15 mm., width 12 mm., depth 7 mm. 
