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Show 334 ECHINODER:MAT A. Second and tubular orifice which may be the lated mouth and a anus( 1). It is in the vicinity of the 1E that we must place CoMATUL the ENCRINUs, Guett.(2) Co tulce with a prolonged disk and Which might be defined(3)T~ b ~naches themselves are articulated a multiatticulated stem. b:ar~n ranges of articulated threads, and dichotomously ~amose,. h ~ler ones at different heights; the b . furmshed wlt sma . the stem emg f h . and the anus on one stde. i . the centre o t e 1 ays, 'fh mouth s m ry small spec. tes-Pentacrinua europteu.s , oms., But one ve . 1 f Europe· it attaches 1tself to va- Monog.-is found m t le seas o ' J'ious Lithophyta. 1' t produce larger and more cotnpli· The seas of hot c Ima es l L the Encr asteriaa, Blum.; sis aster, • cated ones, such as · merous and so various, that · · t however are very nu ' Fossil Encrmt es 1 bgenera according to the com-d' 'd d into severa su ' they have been lVl e 1 b d 1 ced on the summit of the stem and position of the centra o y p a from which the larg~ raysdpr~ce~e~·es articulated with the stem, and Th' body may be lorme o p d ·r th 15 b . '1 r articulations. In this case, a'n 1 e bearing the rays ~ stml a b have the APIOORINITEs, Miller; tem be round and mflated a ove, we s If it be round, but not inflated, ENoRINITEs; If pentagonal, PENTb Al'CRINU~·of angular plates united at the edgu, Or this body may e lOrme . 1 anges Of these and formmg severa r . ges· one of three plates, the The PLATYOIUNITES have but two ran ' other of five; h ges each consisting of five The PoTERIOORINITES have t rec ran ' plates; d each of five, but the last is The CYATHOORINITES also three, an . 't to ten· 1 h' h may mcrease 1 ' furnished with intercalated p ates w llc the first of three, the The Ao'X'INOCRINITES have severa ranges, . . L . Link. xx, 33, xxn, 34; (1) n-terias multiradiata, Zool. Mlscel., loc. Clt., ., ' CXXIV 6 Egypt. JU L' k XXXVII 66· Encyc. ' ' E ncyc., Cxx'r ,· -.9.st. pectinata, L.; m ·, ' ' Echin., I, 1, 2, &c. (2) Acad. des Sc., 1755, P· 224. (3) See Schweigger, Hist. Moll. et Zooph., P· 52 8 . ' PEDICELLAT A. 335 second of five, and the others more numerous. The two first are marked with radiating ridges; The RHODOORINITEs also have several ranges, the first of three, the second of five, and third of ten, all the three with ridges, the others are more numerous. Finally, the central body may be formed of one piece, which appears, however, to consist of five pieces soldered together: here we have the EuGENIAORINITEs( 1 ). The fossil productions, known by the names of Entrochites, are portions of the stem and branches of animals belonging to this genus. EcHINUS, Lin. The Echini, or Sea-Urchins, as they are termed, have the body invested by a shell or calcareous crust, composed of angular pieces which join each other exactly, and perforated by innumerable holes, for the transmission of the membranous feet, disposed in several very regular ranges. The surface ofthis CN.lst is armed with spines, articulated on little tubercles, that move at the will of the animal, whose motions, conjointly with the feet situated between them, they effect. Other membranous tubes, much finer and frequently divided at the ex.tt·ernity, probably serve to convey water into the interior of their shell, and then to remove it. The mouth is provided with five teeth, set in an extrt'mely complex, calcareous framework, resembling a pentagonal lantern, furnished with various muscles, and suspended in a large aperture of the shell. These teeth, which resemble long ribands, become indented inferiorly as fast as they are worn away at the point(2). The intestine is very loug, and attached, spirally, to the interior parietes of the shell by a mesentery. A double vascular system extends along this canal, aqd partly on the mesentery; there are also particular vessels for the feet. Five ovaries, situated round the anus, empty themselves by separate orifices; th~y form the edible portion of these animals. (1) No one hall so carefully 11tudied these productions, or described them so exactly as M. J. Miller, in his Nat. Hist. oftlte Crinoi'dea. Bristol, 1821, in 4to. It is to this work that we are indebted for our article. Excellent figures of the same are also given by M. George Cumberland, in his Reliquia: comerv(l,tm. Bristol, 1826. (2) See Qly Le~ons d' A.nat. Comp., IV, and the work of Tiedemann already quoted. |
