SABELLA. 255 



terior extremity, from 12 to 15 inches in length, and as thick as a 

 common goose-quill, of a hrownish-orange colour more or less stained 

 with the interranea, composed of numerous narrow segments, which 

 are smooth and rather indistinctly defined on the dorsal surface, hut 

 very decidedly so on the ventral and crossed with a longitudinal me- 

 sial groove. Head undefined, the front truncate, surrounded with a 

 free cartilaginous everted scalloped margin divided into two halves 

 by a mesial fissure ; the mouth terminal, nearly central, with a 

 puckered rim, and overlooked by a bilobed organ with a coloured 

 caruncle between it and the dorsal margin. Tentacula two, attached 

 to the cartilaginous base of the branchise, setaceous, smooth, about 

 an inch long. There is besides, attached along the base of the bran- 

 chiae and trending outwards, a sjiirally twisted organ with a free 

 setaceous point. Branchiee attached to the truncate front of the 

 first segment, forming a pair of remarkably elegant large fan-shaped 

 tufts of a straw-yellow colour, beautifully spotted and banded with 

 brown, yellow, orange, green and red, and about 2 inches in height : 

 each tuft consists, in an ordinary specimen, of more than thirty 

 (sometimes as many as eighty or ninety) filaments densely fringed 

 and united together by a common cartilaginous membrane at the 

 base, the rachis striate or annulate when viewed with a common 

 magnifier. The cilia of the fringe are simple, and appear, when 

 magnified, to be divided by pellucid septa like some Confervse. 

 Thorax of twelve nearly equal segments, distinguished by the stig- 

 mata formed by the series of crotchets on each side : the bristles of 

 the foot are numerous, in a round fascicle, unequal, simple, setaceous 

 and sharp, the points of some straight and others obliquely bent. 

 The crotchets are hooked, and so arranged as to resemble the den- 

 ticles of the tongue of a zoophagous mollusk. The abdomen is 

 myriapodous, with similar segments, upwards of three hundred in an 

 entire specimen, the anal one simple, narrowed and emarginate. 

 Each segment is thickened or warted on the sides, and this part 

 affords a more solid foundation to the setigerous conical uniramous 

 foot, and to the linear series of minute crotchets underneath. The 

 bristles are golden-yellow, and collected into a cylindrical fascicle ; 

 and as each bristle is thickened and kneed where the point begins, 

 the apices of the whole are made to converge and form a conical 

 termination. The bristles of the posterior feet become again vmequal ; 

 the longest are setaceous and straight, but the others are like those 

 of the middle feet. 



Inhabits a very long flexible cylindrical tube, formed of fine earth 

 or mud smoothed and cemented by a glutinous secretion. The 

 interior of the tube is lined with a glutinous skin. It is often in- 

 crusted with the Lohularia digitata. 



This magnificent worm was first described by Baster in 17G0. 

 By him it was considered to he identical with the CoraUina tuhidaria 

 melitensis of Ellis ; and this error has continued down to our time, 

 so that the specific name of the worm is difficult to settle. It is not 

 the Serpula jJeniciUus of LinnsBUS in his 10th edition; but the spe- 

 cific character of his Sahella penicillus — " S. testa membranacea 



