. The North American Crinoidea camerata [microform]. Crinoidea, Fossil; Crinoïdes fossiles. Mi'.;. 321 Dolatoorinui exoavatui w. sv. (mv. Bpoc). I'laf. A'AT. Fi>j. /, and I'lat, WW I. T in„l S. A very lnrj(o HpocicH. Doi'kiiI cup »ihiiIIow-biinin hIhuhmI, llin-o timoH nn wido M higli; lliu bottom llatt(MUMl to tlio t()|) of tlio ooxtals; tlio niiIch convex, rnpiilly curvinj^ iipwiinlM, II littlo constrictcil iit tlic arm Imson; f|ii> radiiils formud into a deep, nliarply pentangular, rimnel-Nliii[ii>d pit, which ponotratoH tho calyx almost to tlio heigiit of the
. The North American Crinoidea camerata [microform]. Crinoidea, Fossil; Crinoïdes fossiles. Mi'.;. 321 Dolatoorinui exoavatui w. sv. (mv. Bpoc). I'laf. A'AT. Fi>j. /, and I'lat, WW I. T in„l S. A very lnrj(o HpocicH. Doi'kiiI cup »ihiiIIow-biinin hIhuhmI, llin-o timoH nn wido M higli; lliu bottom llatt(MUMl to tlio t()|) of tlio ooxtals; tlio niiIch convex, rnpiilly curvinj^ iipwiinlM, II littlo constrictcil iit tlic arm Imson; f|ii> radiiils formud into a deep, nliarply pentangular, rimnel-Nliii[ii>d pit, which ponotratoH tho calyx almost to tlio heigiit of the arm ro;>ionH. Siirfacu of platen — except those in tho j)it — covered with parallel riilgen, radiating from tho centre of the plates to their sides, whore they meet with wimilar ridges from ailjoining [)lates. In addition to these ridges there are keel-liko projections following the radials and costals, which grow more conspicuous downward, and at about the top of the radials are produced into a tubercle, which projects into the funnel-shaped pit, nnd gives its npi)er margin a slightly stellate outline. Occasionally the carinate ridges arc continued to the higher brachials, but. as a rule, they becoino obsolete above the second costals. Suture lines slightly grooved. Basals elongate ; forming together with the radials a highly elevated inverted cone with a large pentalobatc canal. Radials large, once and a half ns long as wide; four fifths of tho plates taking part in tho pit, tlic other fifth bending al)ruptly outward ; upper sloping faces short; the lower faces eqiud to one half the greatest width of the plates. First costals small, twice ns wido as long, tluir upper and lower faces convex. Second costals wider than long and slightly wider than the first. Distichals four; tho first os largo as the two costals together. Arnis two to the ray, about equidistant. First interbrachial slightly curving, larger than the radials and first costals together, elongate, widest
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishercambridgemassprint
