5lO DESCRIPTION OF THE MUSEUM. 



into a canal which is often as long as the shell 

 itself in the rostellaria. The last genus, that of 

 the struthiolaria, of which we have but two spe- 

 cies, is very rare. 



5th. The family of the canalifera is composed 

 of three hundred and fourteen species, divided 

 into eight genera, the most numerous of which 

 are the cerithium and the murex. We have one 

 hundred and twenty-three species of cerithium, 

 sixty-four of which are fossil, and fifty species of 

 murex. The murex cervicornis is the rarest of 

 this last genus. The m. cornutus is known by 

 the name of Hercules's club. The shells of the 

 genus murex, which are carved and cut like 

 leaves, are called endives. The rarest of this 

 division is the murex radix. The calcareous 

 stone, out of which the greater part of the 

 houses in Paris are built, has been named cal- 

 caire a cerites because it contains a prodigious 

 quantity of the cerithium coronatum. The cer. ebe- 

 ninum is a very rare shell from the seas of New 

 Zealand. The fusi are remarkable for their py- 

 ramidal form, and the length of their tube. Of 

 the sixty-four species in the collection, thirty are 

 fossil. 



6th. The family of the turbinacea comprehends 

 eight genera, the greatest part of which are 

 worthy of attention either on account of their ra- 



