PEDICULARIA. Sw. A genus of "Scutibranchia," thus described: "Shell irregular, sub-patelliform; a thick, large, obsolete apex on one of the longest sides, and an internal callous rim within, on one side only; circumference undulated, irregular. P. Sicula, Sw." Sw. p. 357. Sicily. A singular shell of the nature of Calyptræa, which is found attached to corals, conforming its shape to the irregularity of their surface, and fitting closely. _Ex._ Fig. 513. PEDIPES. Adanson. _Fam._ Auriculacea, Bl. Colimacea, Lam.--_Descr._ Sub-globose, longitudinal, thick, striated; spire equal to the aperture in length; aperture sub-ovate; peritreme sharp, thickened within, modified by the last whorl; columella with three strong plaits on the inner edge; outer lip with one fold.--_Obs._ This genus contains but one or two small recent species, which in some respects resemble Auricula, from which it is known by the thickness of its shell, and its globular form. Fig. 299, P. Adansoni. Coast of Africa. PEDUM. Lam. (_A shepherd's crook._) _Fam._ Pectinides, Lam. Sub-ostracea, Bl.--_Descr._ Irregular, inequivalve, sub-equilateral, attached by a byssus passing through a sinus in the lower valve; hinge toothless, with a triangular area in each valve, separating the umbones; ligament contained in a groove running across the area; muscular impressions one in each valve, large, sub-orbicular; both valves flat, narrow at the dorsal, broad at the ventral extremities; lower valve with raised edges overwrapping the upper.--_Obs._ This singular genus, of which only one species is known, differs from Ostrea, not only in shape and structure, but also in the mode of attachment, which is by means of a byssus passing through the lower valve, in Pedum, but by a portion of the outer surface of the shell in Ostrea. P. Spondyloideum (fig. 179) is the only species at present known. Moluccas. PEDUNCLE. See PEDICLE. PEDUNCULATED. (_Pedunculus_, a little foot.) Attached to external objects by a hollow fleshy tube, called the Peduncle. PEDUNCULATED CIRRIPEDES. Lam. An order consisting of molluscs which have multivalve shells, supported on a peduncle. The genera which it contains are thus distinguished: 1. PENTELASMIS. Five valves. Fig. 34. 2. CINERAS. Five very minute valves distant from each other. Fig. 42. 3. OTION. The same, but the animal has two auricles. Fig. 43. The genus Palmina, Gray, has but one. 4. OCTOLASMIS. Shaped like Pentelasmis, but with 7 or 8 valves. Fig. 41. 5. LITHOTRYA. Five valves, peduncle scaly with a plate at the base. Fig. 39. 6. SCALPELLUM. Shape square, valves 13, peduncle scaly. Fig. 35. 7. SMILIUM. Same, but the peduncle hairy. Fig. 36.