. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 702 CONCHIFERA. parietes of the foot are preserved in immediate communication by means of a great number of small muscles, sometimes straight, sometimes oblique, and variously interlaced, to which Poli has given the name of funicular muscles (j,j, Jig- 347). They are particularly conspi- cuous in the cylindrical foot of the Solens, in the flattened foot of the Tellinae, and of the Uniones, and they have a remarkable arrange- ment in that of the Cardia. They appear to be wanting in the foot of those Conchiferous mollusks
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 702 CONCHIFERA. parietes of the foot are preserved in immediate communication by means of a great number of small muscles, sometimes straight, sometimes oblique, and variously interlaced, to which Poli has given the name of funicular muscles (j,j, Jig- 347). They are particularly conspi- cuous in the cylindrical foot of the Solens, in the flattened foot of the Tellinae, and of the Uniones, and they have a remarkable arrange- ment in that of the Cardia. They appear to be wanting in the foot of those Conchiferous mollusks that attach themselves by means of a bysstis. In them the foot is reduced to the functions of spinning (de filer) the threads of the byssus, and it is not therefore surprising that its organization should be found to be peculiar. Reduced to a purely rudimentary state, the foot in the Monomyaria (b, jig. 348) appears rather as an appendage to the mass of the viscera than as their defensive envelope. The muscular fasciculi that terminate it pos- teriorly are small; they pass through the vis- ceral mass to be attached either to the superior part of the central muscle, or within the in- terior of the hooks or beaks of the shell. Almost the whole of the Monomyaria furnished with a foot, have a byssus also; to this rule there are indeed a small number of exceptions, among others the Limae. Up to the present time the faculty of pro- ducing a byssus is not known to belong to any other class of animals, and it is limited to a few only of the Conchiferous mollusks. Among the Dimyaria the genus Byssomya may be quoted as an example, also the members of the family of the Mytilacea ; and, if the horny plates of certain Archae be likened to the Fig. byssus, it would also be necessary to include this genus in the group of byssiferous Dimyaria. In the Monomyaria provided with a foot, the whole of the genera are byssiferous, with the exception of those which attach themselves im- mediatel
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