﻿EUOMPHALUS. 249 



nised it, and consequently, as other specimens seemed to show the characters of 

 the shell better, it has not been reproduced. This specimen is slightly smaller 

 than his figure, which fairly represents it, though drawn upon the slant. 

 It has a rather flattened band on the shoulder, and below this on the back are 

 some indistinct and doubtful signs of spiral striae, which are much exaggerated in 

 Phillips's drawing. It appears to be very like fig. 10 of our plate, which would 

 still more resemble it if its surface had not been so much worn away. 



Phillips mentions in his description " some traces of spiral strias ;" these cannot 

 be seen in many of the specimens, probably because they have been obliterated 

 by the decortication which is characteristic of so many Wolborough fossils, and 

 which has more or less affected all the examples of this shell that I have seen. 

 They are, however, to be observed upon one or two of them, as upon Phillips's 

 type specimen, and on the British Museum specimen, PI. XXIV, fig. 11. The 

 specimens from Lummaton, which might have preserved the ornament, are 

 unfortunately only exposed on the umbilical side, and indeed show so little 

 character that it is only presumptively that they can be referred to this species. 



Some of the most distinctive features of the species are the horizontal 

 flattening and falling in of the upper part of the whorls, and the low blunt angle 

 of the shoulder, which seems to be caused by the thickening of the substance of 

 the shell at that point. These characters are seen developed to a much greater 

 extent in the Carboniferous species Eu. sequalis, Sowerby, sp., a and Eu. marginatus, 

 M'Coy. 2 Eu. pentangulatus, Sowerby, 3 another Carboniferous species, has a much 

 sharper and more elevated keel upon the shoulder, and the part above it is 

 inclined at a higher angle to the suture. 



As will be seen from the figures we give, this species is subject to considerable 

 variation. Indeed, if we had a larger number of specimens to judge from, it is 

 possible that they might prove that we have included more than one species under 

 this head. Thus the shell delineated in fig. 10 gives the most usual form ; that 

 given in fig. 9 is a variety with the upper part of the whorl almost quite flat and 

 horizontal, and with a much sharper angle at the shoulder, so that it is hardly to 

 be distinguished from Eu. sequalis, Sow. ; while in that given in fig. 1 1 the 

 differences are so marked that I have separated it below as a named variety. 



Affinities. — Where, as is usually the case with the Wolborough specimens, the 

 surface is much decayed, it often becomes very difficult to distinguish specimens 

 of Pleurotomaria delphinuloides, Schlotheim, from this species. They appear, 

 however, to be distinguished by having a higher spire, and by the whorls sloping 

 downwards and not upwards from the suture to the shoulder. 



1 1816, Sowerby, ' Min. Conch.,' vol. ii, p. 89, pi. cxl, fig. 1. 



2 1844, M'Coy, ' Syn. Carb. Fobs. Ireland,' p. 36, pi. v, fig. 21. 



3 1814, Sowerby, ' Min. Conch.,' vol. i, p. 97, pi. xlv, tigs. 1, 2. 



