248 Dr. T. Wright on the Cidaridse of the Oolites. 



interambulacral arese. It resembles C. maxima, Goldf., in the 

 general outline of the test^ the width of the granular spaces be- 

 tween the tubercles, and in the spines supposed to belong to 

 C. Fowleri being armed with short forward-directed prickly pro- 

 cesses like those of C. maxima. It differs from C. propinqua in 

 having a greater number of plates in the interambulacral arese. 



Locality and stratigraphical range. — Cidaris Fowleri was ob- 

 tained from the ferruginous beds of the Pea-grit at Crickley Hill. 

 I have dedicated this beautiful species to ray friend Charles 

 Fowler, Esq., who obtained two fine specimens from this locality, 

 and to whose generosity I am indebted for the one which has 

 served for my description and enriches my cabinet. 



Cidaris Blumenhachii, Munster. 



Syn. Cidarites Blumenbachii, Munst. ; Goldfuss, Petref. Germanise, 



t. 39. p. 117. 

 Cidaris Blumenbachii, Agassiz, Echin. Foss. 2nd part, t. 21. p. 61 ; 



Park. Org. Rem, vol. iii. t. 4. fig. 1.5. 

 Cidaris florigemma, Phillips, Geol. of York. t. 3. fig. 12. 

 Cidarites Blumenbachii, Munst. ; Cotteau, Etudes Echin, Foss. t. 10. 



p. 108. 



Test circular, inflated at the sides and depressed at the poles ; 

 ambulacral arese narrow, elevated, undulated, and furnished 

 with four rows of granules ; interambulacral arese with two rows 

 of from six to seven tubercles ; areolae approximated, elliptical 

 and excavated, and surrounded by a circle of small tubercles ; 

 spines large, thick, subcylindi'ical, and ornamented with longi- 

 tudinal rows of granules; neck short and smooth. 



Height 1 inch and y'^^ths, transverse diameter 2 inches ; spines 

 1 inch and y%ths in length, and y^ths of an inch in diameter. 



Description. — This typical species was very abundant in the 

 seas which deposited the Coralline Oolites of Europe. It has a 

 globular form considerably depressed at the poles ; the ambulacral 

 arese are narrow, nearly of a uniform breadth throughout ; they 

 are much undulated and furnished with four rows of granules ; 

 the external rows are larger, more regular and prominent, and 

 more developed towards the base than the internal rows. The 

 poriferous avenues follow the undulations of the arese; they 

 are narrow, and lie in a groove formed by the prominent gra- 

 nules of the ambulacral and the external marginal granules of 

 the interambulacral arese. The interambulacral arese are five 

 times as wide as the ambulacral, and are occupied with two rows 

 of large prominent tubercles from six to seven in each row, which 

 are supported on large mammillaiy eminences gradually rising 

 from smooth elliptical areola;. The mammse at their summits 



