234 



HISTORICAL PAL.-EONTOLOGY. 



tionships of which appear to be with some of the living 

 Butterflies of Tropical America. 



Coming to the Mollusca, the Folyzoans, numerous and 



Tig. 164. 



-Eryon arctiforniis, a "Long-tailed Decapod," from the Middle 

 Oolites (Solenhofen Slate). 



beautiful as they are, niust be at once dismissed; but the 

 Brachiopods deserve a moment's attention. The Jurassic 

 Lamp-shells (fig. 165) do not fill by any means such a pre- 

 dominant place in the marine fauna of the period, as in many 

 Palaeozoic deposits, but they are still individually numerous. 

 The two ancient genera Leptcena (fig. 165, a) and Spirifera (fig. 

 165, ^), dating the one from the Lower and the other from the 

 Upper Silurian, appear here for the last time upon the scene, 

 but they have not hitherto been recognised in deposits later 

 than the Lias. The great majority of the Jurassic Bi-achiopods, 

 however, belong to the genera Terebi^ahda (fig. 165, f, e^ f) 

 and Rhy?icho}ieUa (fig. 165, d), both of which are represented 

 by living forms at the present day. The Terebt-atii/ce, in par- 

 ticular, are yqij abundant, and the species are often confined 

 to special horizons in the series. 



Remains of Bivalves i^Lamellib7'aiichiatd) are very numerous 



