616 HISTORY AND METHODS OF THE FISHERIES. 



At the opposite end there is a small opening in the shell corresponding to the anus of the mussel; 

 and in close proximity runs a short fringed tube connecting with the inner organs of respiration. 

 Ou both sides of the mouth there are long, narrow, folded tentacles. Under and behind the base, 

 of the muscles which control the foot, is situated the byssus-spinning gland. From its cavity a 

 groove extends along the lower side of the foot, and ends at its tip in a transverse cavity con- 

 taining a small plate, perforated by seven small apertures, used for sucking. 



Characteristic of tlio mussels is the strong, triangular "foot, "and the "beard" or byssus, 

 a group of silken threads. The foot is the weaver of the mussel's beard, and the manner of 

 secretion of the threads takes place in a fashion quite analogous to that in which the spider makes 

 its thread. From special glands under and behind the foot comes a viscid, semi fluid material, 

 which, run into the groove in the foot, sets therein as a firm thread. This thread is drawn out of 

 the foot by the retraction of that organ, and another thread is rapidly formed, until the beard 

 grows apace, and the mussel has tied itself to something or has tied something to it. This 

 attachment is made early in life to the surface of the rock, log, or other object forming its abode. 

 The second engraving represents the, mussel thus attached. In most cases several tie themselves 

 to each other and to a common object, and thus form large clusters. "Thus a very firm and secure 

 anchorage is effected, and they are generally able to ride out the most violent storms, though, by 

 the giving way of the rocks or shells to which they are attached, many are always stranded on 

 the beaches after severe storms. * * * These shells are not destined to remain forever fixed, 

 however, for they not only swim free when first hatched, but even in after life they can, at will, 

 let go their anchor- threads, or 'byssus,' and creep about by means of their slender 'foot,' until 

 they find another anchorage that suits them better, and they can even climb up the perpendicular 

 sides of rocks or piles by means of the threads of the, 'byssus,' which they then stretch out and 

 attach, one after another, in the direction they wish to climb, each one being fastened a little 

 higher up than the last. Thus, little by little, the heavy shell is drawn up, much in the manner 

 employed by some spiders when moving or suspending an unusually large victim." Though 

 written by Professor Verrill concerning the edible mussel, the words just quoted will apply sub- 

 stantially to all species. 



" The 'beard' of the mussel as a zoological curiosity is interesting enough, no doubt, but that 

 it could by any stretch of the, imagination be regarded as subserving an important function in 

 defending man's structures against the ravages of time and tide is altogether an unlikely supposi- 

 tion. Listen, however, to a recital, as quoted by Mr. Gosse in his manual of the 'Mollusca.' 'At 

 the town of Bideford, in Devonshire, there is a long bridge of twenty-four arches across the Tor- 

 ridge River, near its junction with the Taw. At this bridge the tide flows so rapidly that it 

 cannot be kept in repair by mortar. The corporation, therefore, keep boats in employ to bring 

 mussels to it, and the interstices of the bridge, are filled by hand with the semussels. It is sup- 

 ported from being driven away by the tide entirely by the strong threads these mussels fix to the 

 stone work; and by an act or grant, it is a crime liable to transportation for any person to remove 

 these mussels, unless in the presence and by the consent of the corporation trustees.' Such a 

 history is both curious and interesting, and in the absence of any contradiction Mr. Gosse's 

 'Manual' bears date 1854 the correctness of the narrative may be assumed, if only from an 

 inductive inference concerning the strength of the byssus of the mussels on the beach. The story, 

 besides, presents but another, and, perhaps, novel illustration of the old axiom, L'union fait la 

 force. Utilitarianism may again claim us when we find that a near neighbor of the mussel the 

 Mediterranean pinna manufactures a silky byttsus in sufficient quantity to enable the Sicilians to 



