6 CRETACEOUS GASTROPODA 
Order. PULMONATA, Cuvier. 
Cuar.—Air-breathing Gastropoda with or without a shell; lungs situated im 
Sront of the heart or behind it, and the respiratory cavity opening with a roundish 
hole only ; hermaphrodite, with reciprocal impregnation ; without a metamorphosis, 
the young animal resembling the parent in shape and not provided with deciduous, 
cephalic fins. 
In conformity with the somewhat limited extent of dry land during the 
earlier formations, air-breathing animals seem not to haye been very numer- 
ous, although they were not wanting even in some of the oldest periods. The first 
somewhat doubtful remains of air-breathing Gastropoda are found in the coal- 
measures and not very certain traces were noticed in fresh-water deposits of the 
Lias and Jura. True Pulmonata were described first from the Wealden, but the 
remains even here, and in the cretaceous deposits, are very scarce. By far the 
greatest number, which is calculated to amount to about 600 species, have been 
derived from the cainozoic deposits, the eocene, as well as the neogene. From our 
cretaceous rocks, only a few species have been procured, and these all belong to the 
Sub-order. Stylomatophora. 
the members of which are all terrestrial animals characterized by having their eyes on 
the ends of retractile peduncles, the tentacles being separate and placed below the 
peduncles ; no operculum. 
Fumily.* HELECIDA. 
Subfamily. HELICIN A. 
Except the Boysia Reussii, which was in 1859 described by myself from a 
eretaceous fresh-water deposit in the North-eastern Alps,t I am not aware that 
any species of true Helicinze} have been noticed from deposits lower than the 
eocene strata, although I may be unacquainted with some publications at present 
bearing on this point. The four species, here described under two genera, are, 
therefore, of very great interest, both in the study of the Pwlmonata in general and 
in that of the fauna of the South-Indian cretaceous deposits especially. The greater 
number of our specimens were found in the loose conglomeratic or gritty sandstones 
of the Arrialoor group, or the highest division of the series of deposits, together with 
marine shells. This mode of occurrence increases the interest of these few Helicidee 
very much, and supports Mr. H. Blanford’s statement, that the Arrialoor deposits 
have been formed, partially at least, in very shallow waters.§ Land was evi- 
dently not very far off, and it cannot surprise us, therefore, when we see land shells 
occurring associated with a rich fauna of truly marine species. Helicidee inha- 
bited the shores and islands of the cretaceous sea, and consequently their shells 
* We accept the terminations of—ide and—ine for the denominations of families and sub-families 
respectively. 
7 Sitzungsb. Akad, Wien. Bd. XX XVIII. p. 493, pl. 1, fig. 17. 
£ Helix Gentii, and other species noted by Sowerby are now universally acknowledged as Natica, Trochus, 
ete. § Mem. Geol. Sury. India, Vol. IV, pt. 1, p. 163. 
