A treatise on zoology . as is the case in several crinoids, BB, at least , 5, not notched for reception of ambulacra, but with truncate uppermargin ; they support r> large intcrradially situate A. Each A consists oftwo parts : an orad, subtriangular piece, like that called deltoid in Astero-hlastiu, and a L^wer, triangular i)iece c<n-responding to the pore-plate inAHUrohldstus ; the connection between the two parts is still slight ; indeed,in Canada the orad portions are often fused with one another into a pen-tagonal frame. The lower portions show a marked striation, due to stromast
A treatise on zoology . as is the case in several crinoids, BB, at least , 5, not notched for reception of ambulacra, but with truncate uppermargin ; they support r> large intcrradially situate A. Each A consists oftwo parts : an orad, subtriangular piece, like that called deltoid in Astero-hlastiu, and a L^wer, triangular i)iece c<n-responding to the pore-plate inAHUrohldstus ; the connection between the two parts is still slight ; indeed,in Canada the orad portions are often fused with one another into a pen-tagonal frame. The lower portions show a marked striation, due to stromastrands, at right angles to the radio-deltoid suture, and on the suturaledge the stereom is thrown into folds (incipient hydrospires) which,however, have not been observed to pass into the RU. The food-groovespass out between the A ; the lancet-plate supporting them is covered byalternating side-plates, which receive branches from the main groove, andare provided with a clear brachiole-facet; the remains of brachioles are. THE BLASTOIDEA 8i preserved, as in Asferoblastus and many Eublastoids. These known factsadord no character, other than the less development of the hydrospires,by which Blastoidocrinus should be separated from the Eublastoidea, so
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishe, booksubjectzoology
