A treatise on zoology . ar facets projecting adorally in muscle-plates,corresponding to the muscle-fossae. Genera— (Low. and , Europe), Stylocrijius and Stortingocriniis (Mid. Devonian, Europe),Symbathocrinus, includingXa^, which is probably its young (UpperDevonian and Lower Carboniferous, Europe and N. America). Phimocrinus,Schultze (1866), is primitive in having 5 BE, while all the rest have 3 ;the oldest species, P. Jouherti, Oehlert, shows clear traces of horizontalsuture in r. post., r. ant, and 1. ant. RR, the usual compound RR of typicalHeterocrinidae ;
A treatise on zoology . ar facets projecting adorally in muscle-plates,corresponding to the muscle-fossae. Genera— (Low. and , Europe), Stylocrijius and Stortingocriniis (Mid. Devonian, Europe),Symbathocrinus, includingXa^, which is probably its young (UpperDevonian and Lower Carboniferous, Europe and N. America). Phimocrinus,Schultze (1866), is primitive in having 5 BE, while all the rest have 3 ;the oldest species, P. Jouherti, Oehlert, shows clear traces of horizontalsuture in r. post., r. ant, and 1. ant. RR, the usual compound RR of typicalHeterocrinidae ; the proximal plate of the anal tube is placed as in thoseforms. The latter feature is also found in Htortingocrinus, Schultze (1866),which is notable for having the small unfused B in 1. post. IR, and theangles of the columnar canal radial in position, though the genus is Mono-cyclic. Stylocrinus, Sandberger (1850), has no facet on RR for supportof an anal tube, nor is the usual passage for the rectum seen in the cup-. FiG. of v\\]t of Sjimhuthocrinus. The pinjectioiis on tlic RJi arc muscle-plates. wall ; therefore one cannot orient the small B ; the anus probably piercedpost. O. Syvih((, Phillii)S (1836), has small B in 1. ant. IR, as inPlatycrinidae ; the anal tube rests on the shoulder of r. post. R ; 5 0,all small, post. O being the largest and separated fiom the niuscle-jdatesof the adjacent RR by the passage of the rectum (Fig. LXV.). The familyis not clearly defined, and its Middle Devonian members present remarkable,thougli superficial, resemblances to the contemi>orary Cupressocrinidae. Family 11. Belkmnocrinidak. Monocyclica Inadunata, with 5BB, 5 simple RR, each supporting by a slightly excavate facet an armwliich forks on IBr^ „j. ^ ; each ramus, with numerous sy/ygies in theproximal ]>ortion, ])earing ramuli on alternate sides of most epizygalsand of all ordinary distal brachials ; single narrow anal in radial circlet,resting on
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishe, booksubjectzoology
