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| Keywords: The Quarterly journal of the Geological Society of London (12959975005).jpg THE BEITISn SECOXDART ROCKS 51 <br> 4 ACTINOMETRA LoY I n Sp <br> This fossil consists of the centrodorsal radials and first two <br> brachials of what must have been a large Actinometra The centro- <br> dorsal is exceedingly peculiar and but for my experience with the <br> ' Challenger ' Comatulce I should have been greatly puzzled what to <br> make of it In fact it has been generally taken for the head of <br> a Ptntacrinus to which it has a considerable resemblance except in <br> the absence of external basals ; and even these pieces seem to be <br> wanting in some species of the genus P Fisheri for example as it <br> is at present constituted <br> Actinometra Loveni n sp From the Gault Folkestone <br> Dorsal aspect of the calyx showing the clefts between the first radials and the <br> sides of the centrodorsal which shows no traces of the attachment of <br> cirrhi X 2 <br> In my preliminary report upon the ' Challenger ' Comatulce' I have <br> described how the centrodorsal of some tropical species undergoes <br> a long series of changes in its shape and relations which do not <br> commence until some time after the loss of the stem and the entry <br> upon a free state of existence These changes are pf three kinds ” <br> 1 the loss of all the cirrhi and the gradual obliteration of their <br> sockets ' 2 the lowering of the centrodorsal to the level of the <br> radial pentagon or sometimes even below it ; and 3 the appearance <br> of clefts at its sides between its ventral surface and the dorsal faces <br> of the first radials These three features are combined in various <br> ways in several tropical Comatulce The clefts are largest in Act <br> stellata Ltk and in Loven's Phanogenia tijjnca ; but in the former <br> species the centrodorsal is entirely devoid of cirrhi and altogether <br> below the level of the radial pentagon while in Phanogenia it is a <br> trifle above the level of the radials and bears a few indistinct cirrhus- <br> sockets Act Loveni presents a condition intermediate between <br> these two <br> Proc E S No 194 pp 390-393 <br> e2 36090384 111264 51125 Page 51 Text 36 http //www biodiversitylibrary org/page/36090384 1880 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 36 1880 Geology Periodicals Smithsonian Libraries bhl page 36090384 dc identifier http //biodiversitylibrary org/page/36090384 smithsonian libraries Information field Flickr posted date ISOdate 2014-03-06 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/12959975005 2015-08-26 16 52 28 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1880 Photos uploaded from Flickr by Fæ using a script | ||||
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