132 



CYPHOSOMA. 



Cyphosoma Konigi, Woodward. Mem. Geol. Surv., Decade V, Appendix, 



1857. 



Phymosoma — Biijardin et Hupe. Hist. Nat. des Zooph., p. 508, 1862. 



Cyphosoma — Woodward. " Ou Konig's Sea-urchin," Geologist, vol. v, 



p. 41, 1862. 



— — Cotteau. Paleontologie Fran^aise, t. vii, p. 6/8, pi. 1167, 



1168, 1863. 



Test large, subcircular, depressed, convex on the upper surface, inflated at the sides, 

 almost flat on the under surface ; poriferous zones wide and straight in the upper third, 

 narrow and undulated at the ambitus and base ; pores bigeminal in the upper third, uni- 

 geminal in the lower two thirds of the zone ; ambulacra narrow above, wider below, with 

 two rows of large tubercles, twelve in each ; inter-ambulacra with two regular rows 

 of primary tubercles in the middle, and two rows of secondary tubercles, irregular in size 

 and distribution, on the zonal sides of the area; miliary zone wide, naked, and depressed 

 above, narrow and granular below ; mouth-opening small, peristome circular, lobes nearly 

 equal ; discal opening large, pentagonal ; spines long, subcylindrical ; upper third of 

 the stem acicalate, spatulate, straight or bent ; lower third sculptured with fine longitu- 

 dinal lines. 



Dimensions. — Height seven tenths of an inch ; transverse diameter two inches. 



Description. — This is one of the largest, most beautiful, and typical of our British 

 Cyphosoma; it was well figured by Parkinson, 1811, in his 'Organic Remains,' as "an 

 Echinite from Kent with its spine ;" he gave no description of the specimen, and it was 

 reserved for Dr. Mantell, 1822, to give it a specific place among our Cretaceous 

 Urchins. 



The long list of synonyms prefixed to this article exhibits the historical phases through 

 which it has passed, and the numerous admirable and accurate drawings with which our 

 excellent friend Mr. C. R. Bone has enriched our Monograph will make the determination 

 of Cyphosoma Konigi a matter of ease and certainty to all future observers. 



The specimen figured PI. XXIII, figs. 1 a — belongs to the British Museum. The 

 large test is subcircular, slightly convex above, inflated at the sides, and flattened below 

 (fig. 1 c) ; the surface is highly ornamented, the tubercles are nearly all of the same size 

 and regular in their disposition, and the granules are large and conspicuous at the 

 base. 



The ambulacral areas are narrow above, wide at the ambitus, and contracted at the 

 base; they possess two rows of tubercles, 12 or 13 in each row; those at the ambitus 

 are very large, and nearly equal in size the inter-ambulacral tubercles ; on the upper third 

 of the area they diminish rapidly in magnitude, and from the ambitus to the peristome 

 are much larger. 



At the ambitus the areolae are wide and confluent, but on the upper surface they are 

 narrow and separated only by a line of granules ; the zone which divides the two series is 



