296 NOVEMBER. 



in it were grains of the finest sand. On carefully re- 

 moving all the surrounding tubes and other objects so 

 as to isolate one, we see that it is truly about three 

 inches in length, but that two-thirds of the whole are 

 prostrate and adherent ; this basal portion is horny and 

 pellucid, no mud entering into its texture. The animal 

 when extracted is an inch in length, of which the gill- 

 tufts form one-third. 



Mingled with these there are one or two specimens 

 of a much more imposing species, the Hook-plumed 

 Sabella. 1 It grows to a large size, the crown of gill- 

 filaments sometimes attaining a height of an inch, and 

 the same diameter. The two rows are incurved in 

 regular spirals of half a turn, each consisting of about 

 eighteen filaments, which are rather stout, the whole 

 crown sometimes taking the form of a funnel, some- 

 times that of a cup, often arching inward at the tip. 

 Their pinnae are long and close, the two rows forming 

 a groove, but nearly parallel. Each primary stem is 

 set along the back with twelve pairs of feather-like 

 processes, hooked downwards ; a very remarkable 

 character, and one by which this species may be in a 

 moment distinguished. Their colour is pale red-brown, 

 mottled irregularly with deep brownish purple and with 

 white ; there is a pair of brown specks at the origin of 



1 Sdbetta bombyx, represented in Plate xxxm., towards the right hand, 

 springing out of a group of Serpula tubes. 



