286 
DEVONIAN FAUNA. 
higher on the whorls, the spire seems more elevated, and the enlarged figure of 
the pattern is very different. 
Turho cf. Orbignyamis, Barrois, shows no sinus-band, but the specimen 
described being very poor it is very possible that it may be the same. 
6. Pleueotomabia Neapolitana, n. sp. PI. XXVII, figs. 15, 16. 
Descri]}tion. — Shell rather small, elevated, trochiform. Spire conical, appa- 
rently slightly produced apically, of four or five rather narrow whorls. Suture 
rather deep, but obscured and complicated by the ornament. Whorls spreading 
out obliquely and flatly from the suture to their lower extremity, where they turn 
through a short blunt angle for a short distance to the lower suture. Ornament 
consisting, upon the angle, of three sharp spiral carinas, which are separated by 
furrows, and of which the central is the highest, and, upon the upper flattened part 
of the whorls, of five much less prominent spiral threads, which are crossed and 
reticulated or knotted by very numerous similar straight transverse threads 
sloping slightly backwards from the suture. Sinus-band probably situated 
between the two lower carinas. Base of the shell flat, and ornamented by 
numerous fine spiral lineations. Mouth and umbilicus unseen. 
Size. — Height about 18 mm., width about 16 mm. 
Locality. — There are two specimens in the Torquay Museum which probably 
came from Lummaton or Barton. Another large but rather indistinct specimen 
in the Museum of Practical Geology is from Wolborough. 
Remarks. — These specimens are all so much worn that it is difficult to feel 
certain about the direction of the finer lines, and the markings of the sinus-band 
are almost obscured. It is indeed very hard to say which of the two furrows 
between the large caringe is the sinus-band, for the upper and widest is obscured 
by matrix, and in the lower of the two the cross striae seem much finer, and have 
changed their direction, being either arched or sloping forward. The shell is 
remarkable for its extreme trochiform shape, reminding us strongly of the recent 
Trochus zizijjhimts, but after a very careful examination of the markings I see no 
reason to doubt that it is really a Pleitrotomaria. 
Mr. Roberts was inclined to regard these specimens as large examples of PL 
trochoides, but it appears to me that they are distinguishable from that species by 
several particulars. 
Affinities. — This species differs much from PI. angulata, Sandberger,^ in 
shape, ornamentation, and the position of the sinus-band, and especially in having 
an almost flat base instead of being convex below. 
' 1853, Sandberger, ' Verst. Ehein. Nassau,' p. 204, pi. xxiv, tig. 19. 
