THE SILKWOKM AMPHITEITE. 407 



were at liberty in the sea. Many interesting experiments liave 

 been made upon their modes of working, and by a judicious 

 supply of different substances, they may be forced to build 

 tubes of various colours and forms. 



Very little care is required in keeping the Sabella in the 

 aquarium. The beautiful little worm requires no feeding, and 

 the only precaution that is needed, is to see that the water is 

 pure. All dead animals should be carefully removed from the 

 aquarium, as they are sure to putrefy very quickly, and the 

 noxious gases evolved in that process will soon destroy all the 

 other inhabitants. 



Generally, when the Sabella feels ill, it is obliging enough to 

 come out of its cell and die, in full sight ; but now and then one 

 of them will retreat to the bottom of its cell and die there, in 

 which case it is as noisome and as difi&cult to discover as a dead 

 rat behind the wainscot. Still, although the number of apertures 

 in a single group of Sabella tubes renders it difficult for the 

 possessor to identify the particular tube in which the defunct 

 worm may be lying, its presence can generally be detected by a 

 kind of whitish growth that appears at the mouth of the tube, 

 and that tells its tale to an experienced eye. The best plan of 

 getting out the inmate, is by a slender wire hooked at the end. 

 This can be pushed down to the very bottom of the cell, when a 

 twist of the wire will mostly secure the dead worm, and the 

 nuisance may thus be removed. 



Another species belonging to this genus, the Steaight Sa- 

 bella {Sabella unispira) is remarkable for the form of its tube, 

 which is nearly cylindrical and scarcely possesses any curve 

 at all. 



There is another group of tube-making marine annelids 

 which are remarkable for the transparency of their newly con- 

 structed dwellings. Of these, a very singular example is found 

 in the Silkwoem Amphitkite (AmpMirite horribyx). 



The reader will remember that one, at least, of the Terebellae 

 can make a structure which is as transparent as isinglass, and will 

 not, therefore, be surprised to find that another annelid possesses 

 similar powers. The tube of the Silkworm Amphitrite is longer 

 than the body, and is made entirely of the gelatinous secretion 

 which in most of the species is used as a cement for fastening 



