placoderm a to us (plakodermatus)

Same as placoderm. Placoderm i (plak-ō-dėr'mī), n. pl. [NL.: see placoderm.] An order of fishes, constituted for some remarkable Paleozoic forms of doubtful relationships. It has been variously defined. As usu ally limited, it includes fishes which had a persistent notochord, neural and hemal spines and inter spinals connecting with a dorsal and an anal fin, a jointed pectoral appendage inclosed in a bony covering, the head and front of the body inclosed by bony dorsal and ventral shields, no ventrals, and a distinct lower jaw. Thus limited, it has been made to include the families Coccosteidæ and Dinich thyidæ. Also Placoderm at a, Placoganoidei. placodont (plak'o-dont), n. [ Placodus ( -odont- ).] A member of the group Placodontia or family Placodontidæ. [ML.: see placit, plea.] In the middle ages, a Placodontia (plak-ō-don′shi-ä), n. pl. [NL., the sov sovereign presided, usually summoned to consult upon great affairs of state; hence, a resolution taken by such an a embly; also, a penalty or fine, or a a plea or suit. plack (plak), n. [OF.1 placentitis (plas-en-ti'tis), n . [NL., placenta , placenta, + -it is .] Inflammation of the pla- plache , IMG:content-0309.png:[blocks in formation] Thou placer of plants both humble and tall. Spenser, Shep. Cal., February. placer2 (plas'ér; Amer. Sp. pron. pla-sār'), n. [ conditions the except that no location can include more than 20 acres for each individual claimant, and that, where the lands located under such a claim have been previously surveyed by the United States, the exterior limits of the entry must conform to the legal divisions of the public lands and rectan gular subdivisions thereof. A patent for a placer-claim includes a vein or lode not at the time known to exist with in its limits; but it does not include a known vein or lode, unle so expre ed. placet (pla's et), n. [L., it pleases; 3d pers. sing. pres. ind. of placere : see please .] 1. An que, placque, plecque, in ML. placa, placca ), = MLG. placke, cca ), a coin so called, D. plak, IMG:content-0310.png:[blocks in formation] a spot, a place, village, town, also a patch; a thin slice, a ferrule; cf. MD. placke, plecke, tinct reptiles, represented by the genus Placomixed, in the form blecke, etc., with MD. bleck, blick, a plate, as of tin or lead, D. blik, white iron, tin, OHG. bleh, pleh, plech, blech, MHG. blech, a plate, thin leaf of metal, etc., = Sw. bleck = Dan. blikk, white iron, sheet-metal. Cf. placard, ard, plaque. plaque.] A Scotch billon coin current in the fifteenth century (from 1468), and also in ( πλακ- ), a tablet, plate, + ὁδούς = Ε. tooth.] Α IMG:content-0311.png:[blocks in formation] dus. They are the only known members of the group Placodontia. The general form is unknown. The skull was broad behind, with an apparently compound temporal arcade and a postorbital bar; the teeth around the palate were like paving-stones. The species lived in the Tria ic period. Placodus (plak'ō-dus), n. [NL., genus of reptiles having pavement-like teeth. P. gigas is a species of the Trias. placoganoid (plak-ō-gan'oid), a. and n. [Gr. πλάξ (πλακ-), a tablet, plate, + E. ganoid.] I. a. Having a placoid exoskeleton, as a ganoid fish; belonging to the Placoganoidei. II. n . A member of the Placoganoidei . placoganoidean (plak"ō-ga-noi'de-an), a . and n. [ placoganoid + -ean .] Same as placoganoid . Placoganoidei (plak"ō-ga-noi'dē-i), n . pl . [NL.: see placoganoid .] Same as Placoderm i . placoid (plakʼoid), a . and n . [ πλακοειδής , contr. πλακώδης, flat, εἶδος , form.] I. a . 1. Plate-like: not cent), and under James VI. 8 pence Scotch. ing the dermal investments of sharks, which - Plack and bawbee, to the last farthing; fully. [Scotch.] placket (plak'et), n. [ take the place of true scales and are the o ified papillæ of the cutis. In combination they form the shagreen of the sharks. The name is also extended to the tubercular or thorn-like armature of the skin in rays. on), dim. of plaque, plate: see plack. Cf. pla- 2. Having placoid scales, as a fish; belonging quette, placard.] 1. A pocket, especially a pocket in a woman's dre . When she comes into a great prease of people, for fear of the cutpurse, on a sudden she'll swap thee into her plackerd . Greene, Friar Bacon and Friar Bungay, i. 1. to the Placoidei. See cut under scale. - Placoid exoskeleton, the shagreen, ichthyodorulites, or other forms of the dermal defenses of the elasmobranch i ate fishes. II. n . A member of the Placoidei . Placoidea Placoidea (plā-koi'dē-a), n. pl. [NL.] as Placoidei. IMG:content-0312.jpg:[blocks in formation] merly referred to the marsupials, but by recent writers is coidean (pla-koi'de-an), a. and n. [ +-e- an .] Placoidei (pla-koi'dē-ī), (plā-koi'de-i), n. pl. [NL.: see pla coid.] In Aga iz's cla ification, an artificial group of fishes, having placoid scales: correlated with Ctenoidei, Cycloidei, and Ganoidei. It is mainly equivalent to the cla Elasmobranch i i, but also included the naked marsipobranchs. placoid i an (pla-koi'di-an), n. [