PHASTIANELLA. 321 
mass consists of the usual palate, and a long tongue, sup- 
ported by corneous green plates. In the males, on the right 
side, is a small, green, suboval verge ? The ovarium is of a 
blue milk colour, entwined with the liver, and full of ova in 
July. The branchial apparatus is situate as m all the Littorine, 
and consists of a single pale green arcuated plume, having 
at the anterior end numerous close-set transverse vessels, 
which are long at their commencement and taper gradually 
to near the pericardium. M. Cuvier states that in his Pha- 
sianella he found two plumes; I think our only species has 
but one. 
The foot is not trochidan, except the upper lobe ; the sole 
is a perfect elongated oval, as in Littorina. The locomotive 
functions are curious. When the animal marches, one half 
of the longitudinal area, bounded by a central incised line, 
is first extended and fixed ; the other half is then brought up 
and in lke manner fixed, whilst the first half makes a pro- 
gression, and so on; thus half the foot is alternately in 
motion, giving the animal a lateral oscillatory progress. This 
kind of march is confined, I believe, to this species, and to 
most, if not all, of the true Littorine that have the longi- 
tudinal scission or depressed line of the sole more or less de- 
veloped. The sole is edged with a light lead-coloured line, 
and the upper surface is laterally brindled with semicircular 
broken pik lines. The upper coriaceous brown lobe at its 
posterior end supports a shield-hke paucispiral operculum, 
testaceous, and convex externally ; it then coasts each side of 
the foot, having, as in Trochus, 2-4 lateral, long, setose, 
white, sometimes pale red-brown, or pale green vibracula, 
varying in size, the middle ones being usually the smallest, 
and finally forms on each side the head a scalloped green, or 
pale red neck-lappet, furnished with 6-9 plaim dentations or 
cirrhi, which are more developed on the columellar side ; the 
upper lobe throughout is more or less speckled with red and 
brown streaks. 
This animal, in the beauty of its shell and splendid colora.. 
tion of the organs, is one of the most gorgeous of the British 
Gasteropoda ; the only other animals that can be brought mto 
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