File:A treatise on zoology (1900) (14594260927).jpg

Identifier: treatiseonzoolo03lank (find matches)
Title: A treatise on zoology
Year: 1900 (1900s)
Authors: Lankester, E. Ray (Edwin Ray), Sir, 1847-1929 Bather, Francis Arthur, 1863-1934 Goodrich, Edwin S. (Edwin Stephen), 1868-1946
Subjects: Zoology
Publisher: London : A. & C. Black
Contributing Library: Robarts - University of Toronto
Digitizing Sponsor: University of Toronto

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ound axial canal, ligament-fossa broad andshallow; cirri rare except at root Meso-crinus r. H. Carpenter (1881), Cretaceous,Sweden, Germany; sides of cup slope out-wards ; BB short ; radial facet large, slopesupwards to centre, with larger ligament-fossa ;arms unknown; proximale small and circular;proximal columnals circular, narrowing up-wards ; the rest as in Bonrcjneiicnnu^, but liga-ment-fossa deeper ; cirri sometimes numerous.Rhizocrinus, M. Sara (1864,-08; synn^Cono-crinus, dOrb. ; Democrinus, Perr.), Eoceneto Recent; Atlantic, 73 to (0 IDOO fathoms ;sides of cup slope slightly outwards; bhhigh, may be 7 times height of lUl, oltrnfused ; radial facet slopes upwards to centra,with small ligament-fossa ; IBrj ,„„i o freelaterally, arms not forking; proximale thinand discoidal ; proximal columnals discoidal,those of middle region slender, fulcral ridgebroken at axial canal, arouml wh.e^i theligament-fossa ia concentrated (tig. XLIX.7) ; no cirri except at root (Fig. CXVl. ; see
Text Appearing After Image:
rilE CRINOIDEA 195 also X., XXIII. 4). Family 3. Antedonidae. Pinnata in which thepatina consists of 5 small l^B, not forming a closed circlet, and RR withlarge high muscle-plates and facet approaching horizontal ; cavity enclosedby RR is minute ; mouth endocyclic ; proximal Br loosely incorporated incup ; columnals as in Boui-gueticrinidae, but usually lost in the adult, ex-cept the proximale and adjoining columnals which fuse with one anotherand with IBB to form a single ossicle, the centrodorsal, which bearscirri; root when present, encrusting. 0 and x present in brephic stage,but not in adult. Sacculi almost always present. (See structural details ofAniedon, Figs. IX., XV., XVIII. 2, 3, 4, XIX., XXX., XXXIII., XLVL,XLVIL, XLIX. 8, 9, LIV., LV.) Genera—TVwoW^enmnws, Etallon (1859),Jurassic and Cretaceous of Switzerland, France, and Portugal (Fig. CXVI I.);scarcely differs from Mesocriiuis, excej^t in the reduction of BB andpresence of a cirriferous centrodorsal at the top of the

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