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 Chemnitzice and 

 Eulimcs, the progression is sufficiently active. 



RlSSOA 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 

 fasciae, varying in breadth on the three basal turns, with a 

 yellow one running between them and filling up the inter- 



