GASTEROPODA. 355 
greenish-white, and the intervals black, which last spots are often 
divided by several white lines. 
Figure 459d, profile of the shell and animal; 459e, the animal, 
from beneath. 
There are no two shells more difficult to separate from each other 
than L. viredula and L. zebrina. They both inhabit the same locali- 
ties, and individuals might be selected so widely differing in form and 
colouring as to constitute at least ten species, and it is only by observing 
a large series that their alltance would be allowed. The elevation, 
greater or less irregularity of surface, and the colouring of the spatula 
at the fundus, are not to be relied on. The arrangement of the external 
colours is the most certain diagnostic. In one, when held up to the 
light, the markings are small, triangular, resembling a fine network, 
arranged more densely in the interstices between the ribs. Among 
them are some exactly resembling the figure of Lamarck’s P. viridula, 
in Delessert’s Recueil; and among those we have all varieties, from 
the elevated cone with a striped spatula, from Orange Harbour, to the 
flat, eroded, beautifully marbled specimens from Valparaiso. In JZ. 
zebrina, on the other hand, the ribs are less numerous, and the olive 
colour is arranged in concentric series of large crescentic or arrow- 
headed spots, giving the colour a coarse, zigzag aspect. These vary 
less in altitude, and the central spatula is generally imperfect and 
simple chestuut-coloured or entirely wanting. 
Figure 459 8, flat, eroded variety, with a tortoise-shell spatula; 459 c, 
elevated variety, with striped spatula; 459 f, branchial plume. 
Lorria onycuina (Gould). 
Testa deformis, tenuis, depressa, rotundato-ovata, costis obsoletis radian- 
tibus ad vigintt, et gradibus incrementi confertis laxis notata ; apice 
subcentrali eroso: extus cinerea, mnterspatis costarum plerumque fusco- 
olivacets ; intus lutea castaneo variegata ; margine acuto, wrregulare. 
SHELL small, thin, irregular, depressed, broadly ovate, with twenty 
or more obsolete, unequal ribs. The general colour is ashy green, 
with deep olive stripes between the ribs. Besides this, the whole 
