THE GEOLOGIST. 



FEBRUARY 1862. 



NOTE ON KONIO'S SEA-URCHIN. {CypJiosoma Koenigi, 



Mantell.) 



By S. p. Woodwaed, E.O.S. 



One of tlie commonest fossils of the chalk in the London district 

 is the beautiful Sea- Urchin, of which we here give two figures, from 

 examples in the national collection. It was named by Dr. Mantell, in 

 honour of Mr. Charles Konig, the distinguished German savant, who 

 in his youth was Librarian to Sir Joseph Banks, and became after- 

 wards the Keeper of the Natural History Collections in the British 

 Museum. By the country people in Wiltshire it is called the 

 "Shepherd's Crown." 



The Konig's Sea-Urchin belongs to a subdivision of the old Lin- 

 nean genus Cidaris, to which the name of Gyplioso^na was given by 

 Agassiz (from Kvcjios, curvus ; o-w/xa, corpus). The five ambulacral 

 bands are nearly as broad as the inter-ambulacral, and are ornamented 

 with a double series of tubercles equal in size to the rest. These 

 tubercles are placed on crenulated bosses, but are not perforated as 

 in most of the CidaridcB. 



The upper and under sides of this fossil Urchin are so difierent that 

 drawings of them might be taken to represent two distinct species. 

 The under side exhibits ten pairs of rows of tubercles, largest at the 

 margin, and diminishing gradually to the central orifice. On the 

 upper surface the tubercles are much smaller, and there are two ad- 

 ditional rows on the inter-ambulacral bands, external to those which 

 are continued downwards over the base. This character was pointed 



YOL. V. G 



