228 TELETHUS^. 



plained. Au individual is laid by accident on the surface of the wet 

 sand, and it wishes to bury itself underneath. The body is first dis- 

 posed in an easy line ; and then the anterior part moves of itself and 

 swells out to an oval shape, pointed in front. The proboscis is now 

 extruded, and a portion of the sand lying before it swallowed, so as 

 to make a dimple in the surface. The bulged rings are now con- 

 tracted, and the anterior, fashioned into a conical form, are thrust 

 downwards by a successive series of muscvdar contractions, ring being 

 pushed on after ring ; for all the power is directed forwards by the 

 animal, as the body is held steady, and hindered from being carried 

 backwards by the protrusion and fixation of the bristles of the ven- 

 tral series of feet. The anterior portion being in this manner buried, 

 it is again dilated to the full, by which means the hole is enlarged, 

 and the sand of the sides made more compact, and then this furrow 

 is lined with a glutinous fluid exuded from the skin of the worm. 

 Fixing again the buried part by the ventral feet, the same swallowing 

 of sand and the same series of contractions are repeated ; and thus 

 the process is continued until the whole body becomes concealed in 

 its mine*. It will be noted, that by the process of dilating the an- 

 terior part the calibre of the furrow is wider than is necessary to 

 contain the body, but not wider than necessary to keep the branchiae 

 free from injury and friction as the worm moves rapidly up and down 

 in the tube. These delicate organs can even be displayed in full, 

 and perform their important functions at whatever depth the worm 

 may descend ; and partly to protect them, and partly to filter the 

 water that bathes them, the brushes of bristles that overhang them 

 are protruded amidst and above the vascular filaments, and every 

 bristle is barbed or feathered with lateral spinesf. 



* From this account it is obvious that the worm lives in the hole with the head 

 downwards. Mr. Osier omits the most singular part of the whole process in his 

 account of the method of the Lug's boring, viz. the fact of its swallowing the 

 sand immediately in front, and passing it through the intestinal canal. The worm 

 " bores its way through the sand by means of the peculiar construction of the 

 rings of its head, which, when elongated, has the shape of a regular cone. As 

 each ring is so much smaller than the one behind it as to admit of being received 

 within it, the whole head, when completely retracted, presents a flat surface. 

 When this disk is applied to the sand, the animal, by gradually projecting the 

 cone, and successively dilating the rings of which it is composed, opens for itself 

 a passage through the sand, and then secures the sides of the passage from faUing 

 in by applying to them a glutinous cement, which exudes from its skin, and which 

 unites the particles of sand into a kind of wall, or coating. This covering does 

 not adhere to the body, but forms a detached coherent tube, within which the 

 animal moves with perfect freedom, and which it leaves behind it as it progress- 

 ively advances ; so that the passage is kept pervious throughout its whole length 

 by means of this lining, which may be compared to the lirickvi'ork of the shaft of 

 a mine or tunnel." — Osier, quoted in Roget's Bridgewater Treatise, i. 278. 



t Bellonius's history of this worm is a favourable specimen of his style, and is 

 well done for his time. It is as follows : — " Lumbricus marinus, terrestri major, 

 stabuliitur in littore inter arenam, atque in eo potissimum tractu, quem sestus alti 

 maris contegit : unde interdum discedens siccum relinquit. Piscatoribus ad escam 

 plurimum confert, quem dum consectantur a recrementis, qua; more terrestris 

 super arena relinquit, agnoscunt, qus quo loco perceperiiit, eo pala ferrea impacta 

 lumbricos e profundo extrahere sclent, quos canistris in usum diligenter adser- 

 vant. His natura ad excavandum humum mucorem in anteriore parte dedit, 



