The Cambridge natural history . Fk;. 021.—(iiiir/dditnn Liiiitbtoiie. Fig. -325.—Conch idium section. (I, Doi-sal valve ; , dorsal septum ;s, socket plate ; v, ventrnlvalve ; ns, ventral sejJtuni ;, lieutal plate. it on l)oth valves ; in the doisal valve the fissure is merely thespace between the dental sockets, and may be occvipied by thecardinal process (Fig. 334, C) or covered by a shelly plate—the chilidiuiu. In the ventral valve it gives passage to the pedicle,. Fig. 326.—Stringocephcdus Burtini. (Modified from Woodward.) Devonian. A, Interioro
The Cambridge natural history . Fk;. 021.—(iiiir/dditnn Liiiitbtoiie. Fig. -325.—Conch idium section. (I, Doi-sal valve ; , dorsal septum ;s, socket plate ; v, ventrnlvalve ; ns, ventral sejJtuni ;, lieutal plate. it on l)oth valves ; in the doisal valve the fissure is merely thespace between the dental sockets, and may be occvipied by thecardinal process (Fig. 334, C) or covered by a shelly plate—the chilidiuiu. In the ventral valve it gives passage to the pedicle,. Fig. 326.—Stringocephcdus Burtini. (Modified from Woodward.) Devonian. A, Interiorof dorsal valve. B, Side view of interior of shell ; «, adductor ( = occlusor) scars ;c, crura; , cardinal process; , dorsal septum; , hinge plate; I, brachialloop ; s/J, shelly processes ; , dental sockets ; , ventral septum. and may l)e partly or entirely closed by a similar plate (, d) known as the pseudo-deltidium, especially large inClitamhonites, or remain open {OrtJiis). This pseudo-deltidiumis a primitive character, and arises in an early stage of the TESTICARDINES : INTERNAL CHARACTERS 499 development as a shell-growth on the dorsal side of the animal,Iteeoming attached to the ventral valve subsequently. The pediclein many genera passes out through a special foramen in the beakof the ventral valve; and its proximal portion is often embracedby a pair of small plates—the deltidial plates or deltidium—which are formed on lateral extensions of the ventral mantlelobe, acc
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
