i8: 



HARDWICKE'S SCIENCE-GOSSIP, 



follows. The tube is smooth and hard. By means 

 of the bristles, which may be regarded as long levers 

 or leaping-poles, the animal slowly pushes its lungs 

 and body forth into the water, using the toothed end 

 as a sort of fulcrum ; and by the hooks, to which 

 long tendons are attached, and which are arranged 

 in transverse rows on the under-side of the body, it 

 •can withdraw its soft slimy body into the tube with 

 lightning-like celerity on the approach of alarm, &c. 

 Some of the species can also revolve -in the tube in a 

 curious manner. 



In the genus Sabella the tube is soft, tenacious, 

 and flexible, and is usually made up of a fine mem- 

 brane coated with a layer of smooth fine mud on the 

 exterior. The branchia; have an almost similar 

 structure, situation and function to those of the last 

 genus ; there is no operculum, and sometimes the two 

 small branchial tentacles are absent ; the abdomen as 

 well as the thorax carries both bristles and hooks, which 

 on the former are situated above, and on the latter 

 below the body, S. vesiculosa is about six inches long, 

 .and the branchiae Ijear on their filaments dark-coloured 

 solid globules filled \\i\\\ coloured granules supposed 

 to be eyes; there are eight pairs of setre-bearing feet 

 on the thorax ; the bristles are thickened and serrated 

 near the end, while the hooks are bent at both ends 

 with an entire undivided point ; the tube is leathery, 

 about ten inches long, and coated with sand and 

 fragments of shells. We need merely refer to a few 

 other species of Sabella, such as S. pciiicillns — a 

 most beautiful and extraordinary animal over one 

 foot long, and living some ten fathoms deep in an 

 indiarubber-like tube, some eighteen inches or two 

 feet in length. The creature is provided with very 

 efficient masonic tools, in the shape of a couple of 

 trowels and a scoop, whereby, aided by a secretion 

 from its own body, it prepares the mud as cement 

 for the composition of its tube, shaping tlie material, 

 laying it into position, and smoothing and polishing 

 the whole with tlie finish and dexterity of an accom- 

 plished plasterer ; the branchipe are very large, and 

 exquisitely beautiful in shape and colouring. There 

 is also S. hombyx, notable for its talent in constructing 

 a tube of a silken texture, which it spontaneously 

 exudes from its own body. 



In the genus Terebella we encounter structures 

 ■different in many features from what we have hitherto 

 noticed. The tube is memljranous, and lavishly 

 coated with rather large pieces of shell, gravel, or 

 sand, is open at both ends, and unattached to any 

 foreign body. The anterior grtnglia are fused, while 

 the posterior ones are separate and distinct ; the 

 posterior end of the body bears hooks only, not 

 bristles, while from the fourth segment for a certain 

 specific number we have feet-bearing bristles, with 

 or without hooks. The tentacles are very conspicuous, 

 being very long, extensile, and ciliated organs of 

 touch, prehension, and pulling, penetrated by the 

 peritoneal fluid ; the branchiae, which aerate and 



propel the true blood, are comparatively small and 

 without cilia, are of a red colour, and are erected on 

 two or three of the anterior segments ; there are 

 strong and muscular lips at the opening of the ali- 

 mentary canal. T. littoralis is perhaps the com- 

 monest and the most numerous of all the British 

 marine annelida. When traversing the sandy area 

 between tide levels, we can hardly fail to observe a 

 curious tuft of fibrous threads coated with numerous 

 sandy or gravelly particles, and crowning the orifice 

 of a tube similarly composed, that stands buried 

 erect in the sand for about a foot deep or so. The 

 animal during the ebb-tide remains at or near tlie 

 bottom of this case, and he is an exceedingly wily, 

 vigilant, and wary customer. It is about as difficult 

 to catch him as it is to shoot a curlew. No matter 

 how cautiously, dexterously, and swiftly you bury 

 your trowel, and try to shovel him up, it is all no-go, 

 except under very favourable circumstances indeed. 

 This Terebella, which is about four inches long, 

 bears tentacula that vary in number from 60 to about 

 100, and are of a carnation colour ; the gills are 

 most elegantly branched ; the skin is smooth and of 

 a peach-ljlossom colour, with a bright red stripe 

 down the belly ; the bristles are arranged in sixteen 

 pairs of bundles, and have a smooth double-edged sharp 

 point like a lancet, while the hooks are furnished 

 with one long large tooth with two smaller ones above 

 it. T. ncbiilosa is about six inches long, and bears 

 twenty-three setigerous feet, which are of service more 

 for trowelling, plastering, and polishing the tube, than 

 for locomotion ; there are thick muscular ridges on 

 the under part of the body ; there are three pairs of 

 branchiae ; and the hooks are cut into three teeth. 

 There is also T. textrix (the weaver), which manu- 

 factures a real cobweb as a covering seemingly for its 

 spawn ; and T.figiibis (the potter), which constructs 

 a tube of soft mud or clay. The genus Amphitrite 

 comprises a number of very remarkable forms. 

 Herein the branchiae are usually distributed over the 

 back, and are long prominent appendages bearing on 

 their surface a spirally arranged series of large 

 vibratile cilia, which are remarkably beautiful when 

 seen in motion under the microscope. A single 

 blood-vessel containing the peritoneal fluid penetrates 

 the interior of the organ, and at the extremity thereof 

 returns upon itself. The tentacles of this group are 

 fleshy, unciliated filaments clustered about the 

 mouth, and penetrated by the same fluid ; the feet 

 bear hooks (which appear on ridges extending round 

 the body), and also bristles, and long tactile warts or 

 cirri ; and the tail is provided with bristles, or fleshy 

 appendages. Frequently, when walking by the 

 margin of the sea after a gale, we may observe 

 amongst the multitudinous rejectamenta of the 

 tumbling billows a number of very straight, neatly 

 and trimly made, smooth tubes of the shape of a 

 cheroot. On peering into the broader end of one of 

 these sand- woven cases, we are surprised to observe 



