464 SIPUNCULUS. GEOGRAPHICAL DISTRIBUTION. 



the Echinus. In some, however, this is replaced by a sort of 

 proboscis, which may be protruded or retracted like that of many 

 Annelida ( 835). So great a resemblance, in fact, do such 

 animals bear to certain species which we find in this Class, that, 

 until their structure has been more fully investigated, and the 

 arrangement of their nervous system ascertained, it may be 

 doubted whether their true place is not in it, rather than among 

 the Echinodermata. Nothing can be imagined that is wanting 

 to complete the connection between these two classes, which is 

 established by means of this group. The Sipunculi are seldom 

 found but on sandy shores. They excavate holes in the sand, 

 in which they conceal themselves, occasionally protruding their 

 heads from the orifice. They are much sought after by fisher- 

 men, who use them, like the common lob-worm (Arenicola pisca- 

 torum) whose habits are so similar, as baits for their hooks. 

 Some of them attach stony particles to their skin, by a glutinous 

 exudation, so as to cover it with a hard crust, resembling that 

 formed by some Annelida ( 840). 



1023. In regard to the Geographical distribution of the 

 Echinodermata, it may be stated generally, that all the families 

 of this Class are represented in nearly every portion of the globe. 

 As among other classes, however, so in this, it would appear that 

 the largest species (especially of the Comatula and Pentacrinus) 

 are found in tropical regions ; but Echini, Asteriae, and 

 Holothurice, occur in plenty on our own coasts. Star-fish occa- 

 sionally abound so much on the shores of France, as to be used 

 for a profitable manure. We have no certain knowledge as to 

 the animals which find in the Echinodermata their regular food. 

 Of the Stellerida, Man makes no other use than that just stated ; 

 and of none of the Echinida does he eat any other part than the 

 roe ( 1009). The large use made of the Holothurice by Man, as 

 a source of nutriment, is not generally understood. One species 

 is collected and eaten by the poor inhabitants of the Neapolitan 

 coast; but there is another which constitutes an important 

 article, not only of consumption, but of regular traffic. Captain 

 Flinders (1803) fell in with a fleet of Malay proas, near the 

 Gulf of Carpentaria, on the north coast of New Holland ; and 



