174 



On the Cassidulidse of the Oolites, with descriptions of some new 

 species of that family. By Thomas Wright, M.D. &c. 



Read 16th September 1851. 



Since the publication of my paper* on the "Cidaridse of the 

 Oolites," I have collected two Acrosalenice which are quite new, 

 and an Echinus of the same species as one occurring in the 

 Corallian stage of Besancon, but very rare as a British fossil. 



I now purpose describing these Cidaridse as a supplement to 

 that paper, before entering upon the study of the Cassidulidse, 

 which forms the subject of the present communication. 



Acrosalenia decorataf, Haime. 



Test hemispherical, depressed, outline subpentagonal ; ainbu- 

 lacral areas convex and prominent, the anterior and posterior 

 pair slightly sinuous, having two rows of small perforated 

 marginal tubercles, and the intermediate surface covered with 

 close-set granulations ; interambulacral arese with two ranges 

 of primary tubercles from 10-12 in a range, the four central 

 pairs being alone fully developed ; apical disc large, sur-anal 

 plate central, anus behind encroaching on the single ovarial 

 plate, which is rudimentary and projects far into the single 

 area ; base very concave ; mouth large, in a deep depression ; 



* Ann. and Mag. Nat. Hist. 2nd Series, vol. viii. p. 421. 



t I had given this Acrosalenia another specific name, but just as my 

 MS. was about to be sent to press, I learned that it had been described 

 by M. Jules Haime, under the name Milnia decorata, either in the * An- 

 nales des Sciences Nat./ or in the ' Bulletin de la Soc. Geologique de 

 France,' to neither of which works I can at present refer. I learn further 

 that Professor Forbes has had it drawn and engraved with all the details, 

 and will describe it in the forthcoming decade of his ' Memoirs of the 

 Geological Survey,' under the name A. decorata. I have therefore with- 

 drawn my name and the figure I had intended to give, as the multipli- 

 cation of specific names is at all times to be deplored, but more especially 

 so in our day, when a mania for the creation of species is so rife ; I have 

 therefore much pleasure in referring to the forthcoming decade of the 

 'Memoirs' fat elaborate figures of the anatomy of the test of this beautiful 

 species. 



