GENEEA AND GROUPS OF THE ECHINOIDEA. » 



Genus Lepidocenteus, J. Muller, 1856, Ahhandl. d. h. Akad. 

 d. Wiss. Berlin, p. 258. L. Schidtze, 1867, Denies, d. h. 

 Akad. Wiss. Wien, vol. xxvi. p. 123. Loven, 1874, Etudes, 

 p. 39. Zittel, 1879, Falceont. Bd. i. pt. iii. p. 482. A. 

 Agassiz, 1881, ' Challenger ' Beport, p. 79. {Amended.) 

 Syn. BalcBocidaris, Beyr. 



Interradial areas with from five to nine vertical rows of plates 

 at the ambitus ; plates hexagonal, except close to the ambulacra, 

 where they are quadrangular ; imbrication aboral and also laterally 

 from the median row ; some projection at and over the interradio- 

 ambulacral sutures. 



Ambulacra very narrow, two vertical rows of plates, low and 

 broad, each with a pair of pores. Beyond the peristomial margin 

 the plates are continued to the true mouth, no distinction being 

 possible between coronal and peristomial plates. Tubercles of 

 the interradia distant, there being two or three upon a plate near 

 the ambulacra ; the other plates carry only one or two. Spines 

 subulate and small, but articulated upon tubercles. Jaws 

 exist. 



Fossil. Devonian-: Europe. Lower Carboniferous : TJ. States. 



Genus Kokinckocidaeis, Bollo Sf Buisseret, 1888, Compt. Bend, 

 de VAcad. des Sci. Nat., 26 Mars. 



Shape, apical disk, and jaws unknown. 



Ambulacra broad, with two vertical rows of imbricating plates ; 

 a pair of pores to a plate near the interradial edge ; the pores of 

 the pair oblique, the adoral internal and separated from the other 

 by an oblique ridge ; interporiferous area projecting, carrying 

 numerous secondary tubercles similar to those of the interradial 

 plates. 



Interradia with seven vertical rows of polygonal plates at the 

 ambitus, the median row the smallest ; plates only twice as high 

 as those of the ambulacra, imbricating, carrying rather distant 

 secondary tubercles ; the adambulacral plates carry a larger 

 primary, perforated tubercle near their margin. Spines, some 

 stouter than the others and doubtless belonging to the larger 

 tubercles ; some very delicate and slender, striated longitudinally 

 and more or less cylindrical. 



Fossil. Carboniferous Limestone: Europe (Belgium). 



