ROTELLINA. 
269 
antitorqiiata ;" and in that he was clearly right, as both Miinster's^ and Phillips's^ 
species totally differ from the present form in their elevation, in the rotundity of 
their whorls, and in the position of their sinus-band. 
PI. expansa, Phillips,^ differs, as described from Devonshire, in its flat whorls, 
its more depressed and definitely conical shape, its small suture, and the absence 
of spiral threads. 
Trochus ellijpticus, Hisinger,* seems to be a higher form with straighter sides, 
and to have four or five distant indistinct spiral ridges on each whorl. Giebel ^ 
states it to be the same as Turbo antiquissimus, Bichwald.^ 
Under the name of Trochus oxygonus, F. A. Romer'^ describes a dextral shell 
which is very similar in general shape, but, as it is a cast, it is impossible to say 
whether its ornament agreed, and, moreover, it appears to have a much larger 
umbilicus. 
Flemingia acies, F. A. Romer,^ sp., is a dextral and much more globose shell. 
2. Sub-family. — Umboniin^, Adams. 
1. Genus. — Rotellina, de Koninck, 1881. 
This genus contains small flattish shells with long and highly enveloping 
spires, rounded whorls, and without any umbilicus. De Koninck formed it for 
a single species from the Carboniferous Formation of Belgium. 
1. Rotellina ? helioina, Munster, sp. PI. XXVI, figs. 10, 10 a, 11, 11a. 
1840. EuoMPHALUS HELiciNUs, Munster. Beitr., pt. 3, p. 85, pi. xv, figs. 7 a, b. 
Descriptio7i. — Shell small, lenticular or subdiscoid, very depressed. Spire so 
low as to be almost flat, of four rapidly decreasing whorls. Suture scarcely 
indented. Whorls slightly rising and spreading flatly from the suture, and, 
when they have nearly reached their greatest width, curving round to form a 
1 1840, Munster, 'Beitr.,' pt. 3, p. 87, pi. xv, fig. 12 (Sckizostoma) . 
2 1841, Phillips, ' Pal. Foss.,' p. 96, pi. xxxvii, fig. 176 1^. 
3 1841, Phillips, ' Pal. Foss.,' p. 97, pi. xxxvii, fig. 179 ; and 1836, Phillips, ' Geol. Torks.,' pt. 2, 
p. 226, pi. XV, fig. 4. 
* 1844, Groldfuss, ' Petref. G-erra.,' vol. iii, p. 48, pi. clxxviii, figs. 4 a, b. 
5 1866, Giebel, ' Hepertorium,' p. 97. 
6 1842, Eichwald, ' Urwelt Eusslands,' vol. ii, p. 53, pi. ii, fig. 7. 
7 1843, F. A. Eomer, ' Verst. Harzgeb.,' p. 29, pi. viii, fig. 5. 
8 1850, F. A. Eomer, 'Beitr.,' pt. 1, p. 37, pi. v, figs. 25a, b; and 1884, Clarke, 'Neues Jahrb. 
f . Min.,' Beil.-Band iii, p. 352. 
