GENEEA ATSD GROUPS OF THE ECIIIlSrOTDEA. 173 



Periproct large, superior, more or less remote from the apical 

 system. 



Fossil. Oolite and Cretaceous : Europe. 



It is an unsatisfactory genus, and probably will merge entirely 

 into Pyrina. 



De Loriol, 1888, Faune Cret. du Portug., Ech. vol. ii. fasc. 2, 

 p. 80, describes Pyrina glohosa, which is inseparable from the 

 genus, and obviates the necessity of retaining the genus Globator, 

 Agassiz, 1880. 



Genus Ai^oethoptg-us, Cotteau, 1859, Ech. de la Sarthe, livr. 4, 

 p. 177, pi. xxxi. figs. 1-9 ; 18S3, Ech. Foss. des Pyren. 

 p. 36. Pe Loriol, 1888, Faune Cret. du Portug., Ech. vol. ii. 

 fasc. 2, pi. xiii. 



Test of moderate size, more or less swollen above, low ; almost 

 flat below ; subpeutagonal or circular in outline at the ambitus ; 

 sometimes subconical and moderately high, and slightly trun- 

 cated behind. 



Apical system central, compact, granular at the surface, with 

 four basal plates and five radial plates. Madreporite large, in the 

 right anterior basal, and separating the postero-lateral basals 

 1 and 4, occupying the position also of the posterior basal, and 

 separating the posterior radial plates. 



Ambulacra narrow,- increasing in width to the ambitus, and 

 then narrowing to the peristome. Poriferous zones simple, con- 

 verging above, and pairs simply superposed. 



Peristome elliptical, longest transversely in an opening in a 

 deep impression on the actinal surface; branchial incisions small. 

 No traces of jaws or a perignathic girdle. Periproct flush with 

 the test, large, oblique, irregular, situated between the apex 

 and the posterior margin. Tubercles of the areas small, j)erfo- 

 rated, crenulate and scrobiculate. 



Fossil. Cretaceous (Cenomanian) : Europe. 



III. Subfamily Olig opy gin<B. 

 Tests with very small periproctal openings. 



Genus Haimea. 



Oligopygus. 



The next genus is a very unsatisfactory one. 



