PSEUDOMELANIA. 
237 
which itself runs into Ps. lineata, Sow. might almost be regarded as one species. 
Certainly, it would save much trouble to adopt this view, as is generally done in 
our museums, where nearly every Pseudomelania from the Inferior Oolite is 
labelled Chemnitzia lineata. Sow. In singling out certain forms for specific dis- 
tinction it is not maintained that these do not run into each other ; according to 
the belief now universally accepted they must needs do so. The lineata-procera 
group may be held to embrace such extreme forms as Ps. heterocycla (PI. XVIII, 
fig. 4) and Ps. coarctata (PI. XVIII, fig. 9). In all of them the early whorls are 
smooth, flat, and scarcely project ; presently the whorl is slightly constricted, the 
sutural space widens, and turriting or reversed turriting supervenes. 
Accepting the specific distinctions which it seems convenient to adopt, the 
following species characterise the Lower Division of the Inferior Oolite, viz. Ps. 
procera, Desl. (long variety), Ps. bicarinata, Wright, MS., and Ps. heterocycla, 
Eug. Desl. ; whilst in the Upper Division we have Ps. lineata. Sow., Ps. procera, 
Desl. (short variety), which is nearly the same thing as Sowerby’s species, and 
Ps. coarctata, Desl. 
173. Pseudomelania prooera, Deslongchamps, 1842. Plate XVII, fig. 9, Plate 
XVIII, figs. 1 and 2, 
Plate XXI, fig. 1. 
1842. Melania peoceea, Desl. Mem. Soc. Linn. Norm., vol. viii, p. 222, pi. xii, 
figs. 5, 6. 
1882. Chemnitzia lineata. Sow. Hudleston, Greol. Mag., dec. 2, vol. ix, p. 241, 
pi. vi, figs. 1 and 2. 
Bibliography, ^c. — As before observed, it has been the fashion to refer most of 
the Pseudomelanias of the Inferior Oolite to Sowerby’s species, and thus the 
elongate form in the Dogger was so referred by me. Subsequently I have con- 
cluded that the original Melania lineata^ represents the form in the iron-shot 
Oolite of Dundry, which has smooth whorls with little or no turriting and 
scarcely any constriction. 
Description [N.B. — The chief points of distinction between the members of 
^ It is probable that the name lineata was given by Sowerby with reference to the wavy lines of 
growth, which are really characteristic of the genus. Mr. Tawney (‘ Dundry Gasteropoda,’ p. 16) 
believed the chief characteristic to be the lines of puncta arranged spirally, which, he says, alone 
perhaps enables one to distinguish it from Ps. procera. This structure can only be seen occasionally 
and under peculiar conditions of preservation, and is not of much value for dilFerentiatiou, since it 
may be seen in almost every species of Pseudomelania in the Inferior Oolite, but best in those 
specimens where the outer shell-layer has been partly destroyed. 
