518 APPENDIX. 
paratively long, divergent, thickened, and a little spread at 
the bases; the eyes have decidedly an external bias. The 
operculigerous lobe is certainly without a cirrhal appendage. 
The general colour is dull white, saturated with a mixture of 
minute, confused, snowy, closely condensed matter. The 
convexity of the arcuation denotes the upper parts of the 
animal, and the concavity the ventral range. 
TURRITELLA COMMUNIS.—(P. 331.) 
Exmouth, July 1854. 
The following is the result of another attempt to ascertain 
the quality of the locomotion of this species. Fifty of these 
animals, of all ages, were deposited in a large deep dish filled 
with their native soil, which consisted of a tenacious clayey 
mud mixed with comminuted shelly matter; in this they 
buried themselves in every position from the vertical to the 
horizontal. After three or four hours it appeared, from the 
evidence of a furrow on the mud, that some of these creatures 
had certainly moved, but the progression was so slow as not 
to be perceptible by the eye, and was only seen when a short 
space had been passed. From this experiment it would seem 
that this species has the faculty of effecting a very slow 
march. This inaptitude for motion arises from the shortness 
of the foot, not from the length of the shell; as in other 
animals with elongated shells, such as some Chemnitzie and 
Eulime, the progression is sufficiently active. 
Rissoa FULGIDA.—(P. 357.) 
Exmouth, July 1854. 
This description is entirely reproduced from lively animals 
just examined. The species was originally described by us for 
the ‘ British Mollusca,’ but its almost microscopic size caused 
some of the organs not to be precisely appreciated. 
The shell has four rounded, deeply separated, smooth volu- 
tions, which are spirally encircled by two dullish, red-brown 
fascize, varying in breadth on the three basal: turns, with a 
yellow one running between them and fillmg up the inter- 
