SOLENOCONCHIA. 189 



the west of Scotland has been stopped. All we can 

 boast of is a long annual list of wrecks. We are a 

 people that have had losses ; like Dogberry^ we can 

 afford them : but a superabundance of wealth will not 

 restore disowned mariners to life. The Dentalium is 

 hardy^ and apparently abstemious. Lacaze-Duthiers 

 kept some alive in a flask of sea-water with a little sand 

 for more than eighteen months. It is much more active 

 at night, and sensible of light. A ray of the sun or the 

 flame of a candle will cause it to withdraw its foot. 

 This organ acts as a piston in expelling at the other end 

 the eggs and seminal fluid, as well as perhaps the faeces 

 and exhausted water. The point of the young shell is 

 pear-shaped, and bears some resemblance to a baby^s 

 feeding-bottle with the hole at one end instead of in the 

 middle. It is broken off" when too small to contain the 

 terminal tube or process of the mantle ; and this part of 

 the shell is continually rubbed away as the animal in- 

 creases in size, until at last it becomes truncated, and a 

 short pipe is formed with an oblique slit in front to 

 accommodate the terminal tube. The slit is extended 

 in certain species, although this distinctive character is 

 confined to adult specimens. The inside of the shell is 

 white as porcelain, and brilliant as varnish. The epider- 

 mis is slight and easily abraded. The microscopical 

 texture of the shell is scarcely different from that of 

 Patella, It is most complicated, being composed in a 

 great measui'e of prisms, interlacing fibres, and anasto- 

 mosing canals — not of cellular elements. The quantity 

 of animal matter which it contains is next to nothing. 

 From the above account, which I have mainly derived 

 from the memoirs of Professor Lacaze-Duthiers, it is 

 evident that Dentalium is an object well deserving the 

 study of conchologists. Thanks to him, its position 



