426 HOMES WITHOUT HANDS. 



make the dark sea-mud so adhesive that it is capable of being 

 formed into a tube. 



As may be easily imagined, this tube is extremely fragile, and 

 can not be removed entire from the water without the exercise of 

 much care, its own weight being mostly sufficient to tear it asun- 

 der. The walls of the tube are tolerably thick, and the tube it- 

 self is of some size, measuring nearly half an inch across, and is 

 always found to be protected by the earth upon which it is placed. 

 It is a rather curious fact that the tentacles of this species are of 

 extraordinary length, extending for some eight or nine inches be- 

 yond the entrance of the tube, the animal itself measuring little 

 more than four inches in length. 



The last species of Terebella that will be mentioned is a very 

 small and very remarkable species. It has been appropriately 

 termed the Weaver Terebella {Terebella textrix) from the curi- 

 ous submarine home which it makes. 



Not content with using the glutinous secretion as a means for 

 binding together the muddy particles of which the tube is made, it 

 spins a kind of web, bearing some resemblance to that of the spi- 

 der, and being quite a complicated piece of work. This web is 

 composed of many threads, which are very strong, but are also 

 very fine, and, in consequence, are almost invisible when in the 

 water, and their substance is quite translucent, like the threads of 

 isinglass. The threads encircle the body, and as it is only made 

 in the month of May, when the eggs are deposited, it is in all 

 probability employed more for the sake of guarding the eggs 

 than protecting the body. 



The tube of the Weaver Terebella is very small, not sufficing 

 to cover more than half the body. The worm seems to be more 

 independent of its tube than is usually the case, frequently vacat- 

 ing and returning to it, and sometimes making two or three tubes 

 near each other, and living in any of them which it may happen 

 to prefer at the time. 



We now come to a group of tube-building annelids which are 

 called Sabella), because they live in the sand, and in most cases 

 form their tubes of that material. The general appearance of the 

 tube is extremely variable. In some cases it bears so great a re- 

 semblance to the dwelling of the serpula that a practiced eye is 

 needed to discover the distinction. 



