1869.] LOVEN — ON HYPONOME SARSI. 269 



small irregular calcareous plates and is continued between the 

 arms, and there branches towards the dorsal surface, where it ends 

 with a triangular limitation. The rest of the dorsal surface is 

 covered with a smooth skin of a darker colour, and has in its 

 centre a roundish spot, with many small pores." 



Owing to the specimen described being unique, no account of the 

 anatomy of this remarkable animal is yet given, and its bearing on 

 the obscure and disputed points in the morphology of Echinoder- 

 mata generally, and Cystidea especially, cannot be fully made out, 

 though we may expect valuable suggestions from the pen of the 

 distinguished author. Nevertheless, the evidence given by this 

 astonishing discovery is clearly — 



1. That the "proboscis" in palasozoic Cnnoidea (and, I con- 

 clude, by analogy, that the valvulate "pyramid" in Cystidea, 

 Cari/ocrinus, Agelacrmus, etc.,) is, as in recent Pentacrhii, 

 Antedon, Rhizocrinus, only an anal tube, as maintained by Prof. 

 Wyville Thompson and myself, and has nothing to do with the 

 mouth. 



2. That the mouth can, where it apparently fails altogether, 

 as in most palaeozoic Crinoids, though present, be completely con- 

 cealed through the converting of the ambulacral furrows into 

 vaulted galleries. This will give the clue to the understanding 

 of the true character of many palaeozoic Crinoids. We now 

 understand that these subtegn-inal galleries described by Mr. 

 Billings, and by a contributor to the "Geological Magazine," did 

 not only contain the continuation of the " water-vessels," but are 

 the very ambulacral furrows of Crinoids, Asterids, etc., closed 

 up and converted into vaulted corridors. 



This correct theory of the mouth and anus of paloeozoic 

 Crinoids was, however, as I now learn, given already by Dr. 

 Schultze, of Bonn, in the introduction to his excellent monograph 

 of the Echinoderms of the Eifel limestone, published by the 

 Imperial Academy of Vienna, and bearing the date of 3866. 

 As this book is indispensable to all engaged in the study of 

 palaeozoic Echinodermata, it will not be necessary to give here 

 an extract of his arguments. Happily, this controversy will now 

 be at an end, but the details of the question may yet have to be 

 worked up in many extinct types. 



Note. — In my former paper on Leskia, reprinted in this 

 magazine, several "errata" have crept in, obscuring the meaning 



