DESCRIPTIVE REMARKS. Ixx1 
the Carboniferous Limestone of Ireland; HKwomphalus pentangulatus, 
fig. 8, is particularly abundant in the Limestone, especially in Ire- 
land. Pleurotomaria carinata, fig. 4, is one of a number of species 
included in this genus, common to the Carboniferous Limestone. 
The Hereroropa or Nucrrosrancutata of the Carboniferous rocks 
are of considerable size, if the genus Bellerophon, which is supposed 
to belong to this class, is correctly assigned to it. B. hiuleus, tig. 5, 
is a frequent species in the limestone of England and Ireland. JB. 
Urii, fig. 6, a much smaller species, has a considerable range from 
Upper Devonian strata to the Coal Measures. 
In continuation of the examples already given of some of the 
leading classes of Mollusca, we here introduce (Figure 16) recent 
and fossil Heteropod shells. 
Iie, NG. 
HETEROPODA. 
Atlanta Peronii (recent) S. Atlantic. Bellerophon tenuifascia ( fossil) one-half 
(Woodward’s Mollusca). natural size. Carb. Limestone. 
(De Koninck). 
Plate 14. 
In the Preroropa, also an order of pelagic and swimming Mollusca, 
is included the Paleozoic genus Conularia, which occurs in the Lime- 
stone and Coal Measures of Coalbrook Dale; it is believed to have 
been allied to the recent Cleodora, species of Conularia, have been 
found in Silurian, Devonian, and Carboniferous strata. 
In the woodcut on the following page (Figure 17), of recent and 
fossil Pteropoda- Cresezs, a small living species found in the Atlantic, 
in the form of its shell, may be compared with the fossil genus Zheca, 
several species of which have been alluded to in previous pages, and 
figured on the Plates.* 
* See Descriptive Remarks, ante, pp. Xxi., xxxi., & xliv., also Plates v., viii., xii., 
an| xxvi. 
