158 RADIATA. 



REGULAR. 

 Cidaridse. 

 No. 759. Acrocidaris nobilis, Agass. 



This very beautiful Echinus is subcorneal, and the ambulacral tubercles are 

 much smaller than the interambulacral. It is from the Coral Rag (Middle Oolite), 

 France. Price, $0.30. 



No. 760. Archaeocidaris Agassizi, Hall. 



This ancient representative of the Oidaridw has on each of the interambu- 

 lacral plates a large tubercle, perforated and surrounded with a high ring. The 

 specimen is from the Burlington limestone (Sub-carboniferous), Burlington, Iowa 



Price, $0.30. 

 No. 761. Archaeocidaris "Wortheni, Hall. 



Group. From the St. Louis limestone (Sub-carboniferous), St. Louis, Mo. 



Size, 8x3. Price, $0.60. 

 No. 762. Cidaris coronata, Goidf. 



Two specimens. In the Cidaris proper the form is symmetrical, the 

 tubercles are perforated, the ambulacra narrow, 

 and the two lines of pores close together. This 

 species is depressed, and its tubercles are few in num- 

 ber and of large size. These specimens are from 

 the Coral Rag (Middle Oolite), Nattheim, Wir- 

 temberg, and belong to the Ward Museum, Univer- 

 sity of Rochester. Price, $0.60. 



No. 763. Cidaris clavigera, Koenig. 



Group of spines. The tubercles of this species are large and imper- 

 forate ; the spines are large, clavate, and crowded with longitudinal, prickly ribs ; 

 the test is of medium size. This specimen is from the Upper Chalk, England, 

 and now in the Ward Museum, University of Rochester. Price, $0.75. 



No. 764. Cidaris Drogiaca, Cotteau. 



This is one of the largest of all the known species. From the Jurassic lime- 

 stone of Druyes, France. Price, $0.60. 



No. 765. Cidaris pleracantha, Agass. 



Spine. The spines of this remarkable species, by which it is chiefly known, 

 are subcylindrical when small, ovoid when of medium size, and pyriform when 

 large. They are always covered with very fine longitudinal stria?. This speci- 

 men is from the White Chalk of Meudon, France. Price, $0.20. 



No. 766. Cidaris subvesiculosa, D'Orb. 



Group of spines. The tubercles of this species are proportionally small, 

 and encircled with very distinct rings. The spines are long and slender. 

 From the Upper Chalk of Kent, England, and now in the Ward Museum, Univer- 

 sity of Rochester. Price, $0.50. 



No. 767. Cidaris venulosa, Agass. 



From the Mtestricht beds (Cretaceous), Northern Europe. Price, $0.50. 



