TEREBELLA. 194 
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 branchie 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 littoralés 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 conchilega 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 branchiz and general appearance. 
Phate XXVI. 
Fic. 1. Terebella littoralis—The Sand Mason—Tentacula a; branchiz &. 
Section of the body. 
Section of one of the branchiz, enlarged. 
bo 
Section of a part, magnified. 
Terebella in its tube, partly on the side of a glass. 
Tuft terminating the tube. 
SA tes) 
Substances of uncertain nature discharged by the Terebella. 
§ 2. TeREBELLA FIGULUS—T'he 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 
