Mr Etheridge on a Sinall Naticiform G aster opod. 165 



in some young specimens, I believe I can detect a small um- 

 bilicus ; but when the inner lip is at all reflected, the shell is 

 to all intents and purposes non-umbilicate. 



Not the least interesting feature about these little shells is 

 the retention of the bands of colour. This phenomenon is 

 occasionally met with in Carboniferous Mollusca, more par- 

 ticularly those from the Derbyshire Limestones. It has been 

 noticed in some forms of Terebratula, Lingida, and Aviculo- 

 pecfen, and in some Gasteropoda. In the present instance the 

 bands of colour are displayed after two different patterns, 

 horizontal and vertical to the longer axis of the shell, and 

 always confined to the body whirl. The horizontal bands are 

 two in number in every case (PI. III., Figs. 4 and 5), one oc- 

 cupying the periphery, or most prominent point of the whirl 

 (PL III., Fig. 4), the other much lower down towards the base 

 (PI. III., Fig. 5). These bands are of variable width, in some 

 cases broad, and occupying nearly the whole of the whirl, in 

 others quite narrow, linear, and far apart. In the second 

 variety the colour bands are much more numerous, and more 

 or less vertical to the longer axis, i.e., they follow and coincide 

 with the thread-like lines of growth. 



Even amongst this latter form of the Craigkelly univalve 

 variation is likewise apparent. In one specimen the bands 

 of colour are numerous (PL III., Fig. 1), in others less so 

 (PL III., Fig. 3), and further apart ; in one placed at equal 

 distances apart, in another arranged in contiguous pairs (PL 

 III., Fig. 2), with a wide interspace separating them ; lastly, 

 the bands are either direct, or zig-zag (PL III., Fig. 6), and 

 in some instances broken or interrupted in their course over 

 the body whirl. In no case have both vertical and hori- 

 zontal bands been observed in the same specimen. 



Generic Affinities. — We may now pass on to consider the 

 af&nities of these remarkable little shells. In the first place, 

 some writers might possibly be induced to separate the shell 

 from Eaw Camps, from that found at the Craigkelly Quarry, 

 on the strength of the somewhat higher spire of the former 

 variety ; but when we consider to how great a length varia- 

 tion undoubtedly goes in some of the commoner Mollusca of 

 our shores at the present day, I think the little fossils from 



