THE GEOLOGIST. 
FEBRUAEY 1862. 
NOTE ON KOXIG'S SEA-EECHIN. {Cypliosoma Koenigi, 
Mantell.) 
By S. p. AVoodwaed, E.G.S. 
One of the commonest fossils of the chalk in the London district 
is the beautiful Sea-Erchin, of which we here give two figures, from 
examples in the national collection. It was named bv 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-Erchin belongs to a subdivision of the old Lin- 
nean genus Cidaris, to which the name of Cypliosoma was given by 
Agassiz (from Kvcftos, curvus ; o-w/xa, corpus). The five ambulacral 
bands are nearly as broad as the inter-ambulacral, and are ornamented 
M'ith 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 Cidaridce. 
The upper and under sides of this fossil Erchin are so different 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 
TOL. V. G 
