MANUAL OF NATUKAL HISTORY. 327 



been revealed to science. A curious form (Rhopalo- 

 dina) has been lately described by Dr. Gray, which 

 presents many striking affinities both with the Ho- 

 lothurice, and with the Vermigrada ; judging from 

 the published description that the former predo- 

 minate, we have placed it provisionally among 

 the Cirrho-Vermigrada. 



From the numerous fossil remains of animals of 

 this Class, they appear to have been very abundant 

 during former eras. They occur in Palaeozoic rocks, 

 also in various parts of the Oolitic and Cretaceous 

 systems, and in many tertiaiy formations. Among 

 the most singular are the Encrinites, or " stalked 

 Pinnigrada," now nearly extinct. Their remains are 

 popularly known as " Lily-stars/' and fragments of 

 the stalks or peduncles, from occurring plentifully 

 in Holy-Island, were by our pious ancestors named 

 " St. Cuthbert's beads/' according to the tradition, 

 that 



" On a rock by Lindisfarne, 

 St. Cuthbert sits, and toils to frame 

 The sea-born beads that bear his name.'' 



Accordingly, in the middle ages they were strung 

 and used as rosaries, being in Germany, also, known 

 as " bead-stones/' or " St. Boniface's pennies/' 



Among the Malays and Chinese some Holothu- 

 rian species are used as food under the name of 

 " Trepang ;" and in Europe the Common Sea-urchin 

 (Echinus esculentus) is, as its specific name implies, 

 frequently accounted edible. In some parts of the 

 Mediterranean, especially among the islands of the 



