A treatise on zoology . and abactiiml surface unknown ; but the genus appears to THE EDRIOASTEROIDEA 209 connect this family with the more primitive forms of Billings (1858), Ordovician, Canada (Fig. VI.), also includes^^ Agelacrinites BuchuDius, Forl)es (1848), from Wales. Theca about halfas high as wide, depressed slightly at oral pole. Rays curved, all orsome sinistral or dextral, passing on to under surface of theca ; ambu-lacra! groove floored by alternating plates [? adambulacrals], between whichwere pores [1 for podia] ; with covering-plates, ambulacrals,
A treatise on zoology . and abactiiml surface unknown ; but the genus appears to THE EDRIOASTEROIDEA 209 connect this family with the more primitive forms of Billings (1858), Ordovician, Canada (Fig. VI.), also includes^^ Agelacrinites BuchuDius, Forl)es (1848), from Wales. Theca about halfas high as wide, depressed slightly at oral pole. Rays curved, all orsome sinistral or dextral, passing on to under surface of theca ; ambu-lacra! groove floored by alternating plates [? adambulacrals], between whichwere pores [1 for podia] ; with covering-plates, ambulacrals, overthe groove. Interambulacrals non-imbricate. Under-surface of thecaexcavate, its central region composed of a flexible membrane set withminute imbricating plates, and in a frame of about 11 large the animal was attached by the central part of this membraneis doubtful; immediately round the centre this is evaginated in five lobes,apparently caused by the pressure of some internal organs [? gonads], emb.
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishe, booksubjectzoology
