. Echinoidea. Sea urchins. ECHINOIDEA. II. 89 understand the true relationship not only of niany aberrant groups of Spatangoids, liut also tlieir relationship to the Clypeastroids and Echinolampadæ \ (â Cliall. -Ech. p. 148). I give liere a graphic representation of the niutual relationship of the Spatangoids, as I under- stand it. It will be seen that m\- view of the Mcridostcriiaia is in rather close accordance with that represented in the tabular view of the Mcridostcriii given by ; I nia\- notice expressly that it is not nieant as a genealogical tree of the genera. As for the
. Echinoidea. Sea urchins. ECHINOIDEA. II. 89 understand the true relationship not only of niany aberrant groups of Spatangoids, liut also tlieir relationship to the Clypeastroids and Echinolampadæ \ (â Cliall. -Ech. p. 148). I give liere a graphic representation of the niutual relationship of the Spatangoids, as I under- stand it. It will be seen that m\- view of the Mcridostcriiaia is in rather close accordance with that represented in the tabular view of the Mcridostcriii given by ; I nia\- notice expressly that it is not nieant as a genealogical tree of the genera. As for the families, I do not doubt that they have reallv been dcrived from one another in the direction hcre indicated. Plexechinus Cystechinns(?)- Pileniatechinus Urechinus Echinosigra Spatagocystis Ceratophysa C3stocrepis Helgoc)stis Echinocrepis Calymnidæ Sternopatagus ^~ %\ Stereopneustes Ananchytidæ. CoUyritidæ Clypeastroidea o O Holectypoidea Spatangidæ 3 Palæostomatidæ Palæopneustidæ Aéropidæ. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Mortensen, Th. (Theodor), 1868-1952. Copenhagen, Printed by Bianco Luno
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1900, bookyear1903
