SEA-URCHINS. 91 



same preparation as other Star-fish, only that much caution is 

 required. 



When these are packed, they will require great attention. 

 The larger kinds should be wrapped in fine and soft paper, 

 and the smaller ones packed between layers of cotton. 



Echini and Spatangus? SEA-URCHINS. 



There is a great difficulty in preserving these animals, in 

 consequence of the spines with which they are invested, prin- 

 cipally from the care required in retaining the natural positions, 

 the spines of which are, in many species, pointed in all di- 

 rections. This is particularly the case with those of the 

 genus Cidarites. These animals inhabit the Mediterranean 

 and Indian seas, and are distinguished by the shells having 

 large tubercles, pierced with holes, for a muscular cord which 

 moves the spines. These spines are extremely large, solid, 

 and heavy, and are very liable to fall off, even from their own 

 weight while drying. 



The anal opening should be a little enlarged, a small spatula 

 introduced, and the whole intestines removed ; it should then 

 be immersed in fresh water for a quarter of an hour, taking 

 care to preserve the spines. When taken out, fill the shell 

 with cotton ; the shell should then be placed on a plank to dry, 

 and between each spine a pad of cotton, to prevent the weight 

 of the shell resting on the spines, and also to keep those on 

 the upper surface in their proper place, and so that they may 

 all radiate from the body of the shell. 



In sending them home, each should be separately packed, 

 retaining the cotton between the spines, placing them in a 

 box, so that they cannot rub against each other, and with a 

 thick padding of cotton between each. Small species should 

 be placed in little boxes, and packed as above directed. 



Nothing is more difficult than to preserve entire the spines 

 of these large shells, and it is seldom that the larger species 

 can be kept complete. But these can be again fixed, if they 

 have fallen off. The whole spines of the Echini and Spatangi 

 are seated on small tubercles. A little hole must be drilled 

 in the end of each spine, at its base, with a triangular awl, or 

 a saddler's awl, to the depth of about a quarter of an inch ; 



