THE FAN SABELLA. 2?7 



Finally, n common species has its case horizontal and adherent throughout, to its supporting shell or 

 ?tone. It id generally found on old bivalve shells, is cylindrical, open at both ends, sinuous, and from 

 six to ten inches long, thicker than a quill, and is coated with shell and gravel and pieces of 

 Sertularia. 



One of the Tubicolae, which forms its tube of agglutinated grains of sand, has its home free, conical, 

 and widely open at both ends. The ill-defined head has a row of prominent bristles in two fan- 

 shaped sets above the mouth, which is overhung by a fringe of short channelled tentacles. The 

 branchiae are in two pairs, on the sides of the third and fourth segments. The thoracic portion of the 

 body is greatly developed, and the segments form setigerous feet on each side, but the tail end is 

 small and indistinctly segmented, and has no feet. Pectinaria belgica, which has a straight tube, lives 

 on the sandy shores, within the lowest tide-mark. It varies from two to five inches in length, and 

 stands immersed in the sand perpendicularly , and when active, searches all around the opening with 

 its tentacles for grains of sand, shortening, lengthening, and twisting these organs in a most work- 

 manlike manner, and applying the grains to the top of the rim of the tube. The animal can turn in 

 its tube, which is as thin as paper, for only a single sand grain is placed one over the other, and the 

 whole is lined with a slight silky coating within. It is the type of the family Amphictionidae, whose 

 genera are world-wide. 



The last family to be noticed forms either calcareous or membranous tubes, and contains some of 

 the most beautiful objects of the aquarium. The Serpulidae have a vermiform body, with short 

 segments usually well divided into two regions, the front, or thorax, and that behind, or the abdomen. 

 The cephalic lobe is continuous with the next ring, which usually has a collar. The mouth is situate 

 between spiral or semicircular branchial fans or laminae, more or less supported by a dense tissue. 

 There are two or three tentacular cirri. The dorsal lobes of the feet carry fascicles of simple setae 

 in the front part, and the ventral lobes hooked setae. la the hinder part, the hooks are 011 the 

 upper lobes, but they are often absent, and the ordinary setae also. 



There are two sub-families, the Sabellmse and the Serpulinae. 



Dr. Baird writes : " A very handsome species, and one of the most common found on our 

 coasts, is the ' Fan Sabella ' (Sabella penicillus). The animal is from twelve to fifteen inches 

 in length, and as thick as a common goose-quill. It is of a brownish-orange colour, and 

 composed of numerous segments. There is no proper head, but the anterior extremity is 

 furnished with branchiae, which form a 'pair of remarkably elegant, large, fan-shaped tufts, of 

 a straw-yellow colour, beautifully spotted and branded with brown, yellow, orange, green, and 

 red, and about two 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 cilia of the fringe are simple, and 

 the uncini, or hooked setse, are arranged in such a way ' as to resemble the denticles of the tongue of 

 a zoophagous mollusc.' The bristles which their feet bear ' are of a golden yellow, collected into a 

 cylindrical fascicle ; and as ea?h bristle is thickened or kneed where the point begins, the apices of 

 the whole are made to converge and form a conical termination.' The tube in which this worm lives 

 is long, flexible, and cylindrical ; smooth outside, the mud or fine sand of which it is constructed 

 being cemented by a kind of glutinous secretion. In some of our creeks and tidal rivers these 

 animals abound in immense numbers, and on the coast of Essex they are known to the fishermen by 

 the name of ' Hassocks.' When dredging in the river Roach, I have often come upon banks where 

 they existed in hundreds of thousands, and appear in masses of large extent, growing erect like a 

 standing field of corn." 



Sir J. Daly ell gives us a very interesting account of this fine species, under the name of 

 Ainphitrite ventilabrum. He describes it in great detail, and the foraiation of its tube is given with 

 graphic accuracy. The little organs which he caHs "trowels," and the "scoop," are extremely useful, 

 as the following account clearly shows : " To catch and collect the muddy material necessary for 

 the work, the branchial fans are spread out into a semicircle, so that when the two are brought into 

 contact a wide funnel is formed. Once in the funnel, the muddy matter is forced down the rachis of 

 the filaments by the play of the ciliary fringes, and brought within reach of the singular organ at the 

 base of the funnel by which the mud is selected and applied, just as a mason would, lay lime on with 



