TEBEBELLA. 191 



the animal is so little affected, that its labours are not only commenced, 

 but continued under such privations. 



Slight injuries often prove fatal, especially in hot weather. When- 

 ever the body acquires a greenish tinge, the conservation of a specimen 

 is a vain attempt. The vivid red of the branchias and the other parts 

 exhibits the same conversion of colour. Some contract or disappear in 

 death, insomuch, that the creature once so active and industrious can 

 scarcely be recognised. 



Like the Amphitrite, the Terebella in dying quits its tube. 



This species, the Terebella littoralis or arenaria, is thus named from 

 the place of its abode, and the materials of its architecture. It must not 

 be confounded with the Terebella conchilcya or shell binder, which dwells 

 in deep water, and from which it may readily be distinguished, first, ex- 

 ternally by the materials of its tube ; next, the different configuration of 

 the branchiae and general appearance. 



PLATE XXVI. 



FIG. 1. Terebella littoralis The Sand Mason Tentacula a ; branchiae b. 



2. Section of the body. 



3. Section of one of the branchiae, enlarged, 



4. Section of a part, magnified. 



5. Terebella in its tube, partly on the side of a glass. 



6. Tuft terminating the tube. 



7. Substances of uncertain nature discharged by the Terebella. 



2. TEKEBELLA FIGULUS The Potter. Plate XXVII. Figs. 1, 2. 



As the history of genera can be composed only by viewing species, 

 wherein must be comprehended both aspect and habits, naturalists would 

 do well to avoid the oversight of either. 



We are wont to consider the strongest demonstrations of instinct as 

 a wonderful prerogative, inherited from Nature by those diminutive 

 beings incorporated with the great, numerous, and extensive class of 

 insects. But it must be admitted that they are rivalled by the subjects 



