MAKE A MEME
View Large Image
| View Original: | The_Quarterly_journal_of_the_Geological_Society_of_London_(13206139854).jpg (1199x2069) | |||
| Download: | Original | Medium | Small | Thumb |
| Courtesy of: | commons.wikimedia.org | More Like This | ||
| Keywords: The Quarterly journal of the Geological Society of London (13206139854).jpg 252 <br> PROCEEDINGS OF THE GEOLOGICAL SOCIETY Mar 10 <br> the neck-segment in all Trilobites ; the latter segment in our genus <br> is armed with a spine <br> rr <br> Fig 1 Trinucleus ornatus <br> 2 Do magnified fringe <br> 3 Hypothetical development of the fringe <br> 4 Fringe of T fimbriatus <br> The body-rings are six very flat and capable only of bending or <br> doubling not of rolling up as in Calymene a character of considerable <br> importance inasmuch as it has relation to the connecting membranes <br> and articular surfaces of the crust species capable of rolling into a <br> ball requiring large articular surfaces on the segments to enable them <br> to move freely on each other ; and a fulcrum as centre of motion on <br> the side pieces of each segment is generally placed about one-third of <br> the distance from the axis in Trinucleus the rudimentary fulcrum <br> is quite at the extremity of the segment and apparently useless <br> The tail generally smooth has a deflected border but not as far <br> as observed a striated internal fold so common in higher forms of <br> Trilobites <br> The peculiar perforate border is the most interesting part of these <br> animals and I propose to examine it critically <br> The puncta are almost always arranged in radiating rows three <br> four or more holes in each row and these being at equal distances <br> they form concentric lines In T granulatus two of these rows are <br> separated by a furrow from the rest ; in T seticornis three are distinct <br> from the remaining two or three by the front rows being sunk in a <br> deep concentric furrow Other modifications take place in T jimhria- <br> tus the two front rows are turned downwards ; lastly in T ornatus <br> for by that name we must call T Caractaci the dots occur most <br> frequently in quincunx order i e the radiant rows appear zigzag <br> and not direct fig 2 this appearance is due to the great obliquity <br> of the rays 2 a a I wish to call attention to this because I con- <br> sider it enables us to understand the nature of the enigmatical puncta <br> If we suppose a head furnished with a produced membranous margin <br> fig 5 instead of a perforate one we shall get at the explanation 36932991 113687 51125 Page 252 Text v 3 http //www biodiversitylibrary org/page/36932991 1847 Geological Society of London NameFound Calymene NameConfirmed Calymene EOLID 4322334 NameBankID 2875639 NameFound Trilobites granulatus NameConfirmed Trilobites NameBankID 4377238 NameFound Trilobites ornatus NameFound Trilobites seticornis NameConfirmed Trilobites NameBankID 4377238 NameFound Trinucleus NameConfirmed Trinucleus EOLID 4324924 NameBankID 2875667 NameFound Trinucleus fimbriatus NameConfirmed Trinucleus fimbriatus NameFound Trinucleus ornatus NameConfirmed Trinucleus ornatus Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 3 1847 Geology Periodicals Smithsonian Libraries bhl page 36932991 dc identifier http //biodiversitylibrary org/page/36932991 smithsonian libraries Information field Flickr posted date ISOdate 2014-03-17 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/13206139854 2015-08-26 12 55 10 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1847 Photos uploaded from Flickr by FĂŚ using a script | ||||
.jpg){kind=link}
