182 PROF. p. M. DTTNCAlSr'S RETISIOK 01' THE 



Fossil. Cretaceous : Europe, Asia, IST. Africa, W. Africa, and 

 N. America. Eocene : Europe, Asia, N. America. 



Subgenus Ehtnchopygus, d'Orligny, 1855 (genus), Pal. Fran^., 

 Terr. Cret. vi. p. 324. A. Agassiz, 1872-4, Bevision, 

 pp. 342, 553. 

 Cassidulids having a test with a rostrum overhanging a trans- 

 versely elongate supramarginal periproct. 



Fossil. Cretaceous : Europe. Eocene : Europe, Africa, Asia. 

 Late Tertiary : Gruadeloupe, "W. Indies. 



Mecent. Caribbean Sea, Panama, California, Gralapagos. 



Subgenus PTGOESYisrcHUS, Agassiz, 1839, Echin. foss. Suisse, 

 p. 53. 



Syn. Cyrtoma, M'Clelland, 1840. 



Test moderate in size, tumid abactinally, concave actinally. 

 Petals long. 



Peristome longest transversely, with a well-developed flosceUe. 

 Periproct supramarginal and transverse. A more or less bare 

 median band in the posterior interradium actinally. 



Fossil. Cretaceous: Europe, Asia. Eocene: Europe. Mio- 

 cene : Europe, America, Australia. 



Genus STiaMATOPTGus, d'Orligny, 1855, PaZ. Franc, Terr. Cret. 

 vi. p. 331. Desor, 1858, Synopsis, j). 296. Stoliczlca, 1873, 

 Cret. Fauna S. India, Mem. Geol. Surv. Ind., Pal. Ind. 

 ser. viii. vol. iv. pt. 3, p. 27. 



Test of moderate size, ovate in marginal outline, subhemi- 

 spherical, flat actinally. 



Apical system subcentral, with four basal plates, the madre- 

 porite in the largest, the right anterior ; the basal plates perforated 

 by genital ducts except the right anterior. 



Ambulacra petaloid, narrow, moderate in length, none reaching 

 the margin, unequal, narrowed distally, the anterior the longest. 



Interradia finely granular actinally, with coarse mamillated 

 tubercles most numerous at the floscelle, large and finely tuber- 

 culated abactinally. 



Peristome slightly depressed, large, subpentagonal ; floscelle 

 greatly developed, the bourrelets long and tumid, and projecting 

 into the peristome, and the ambulacral lips angular, large, and 

 projecting inwards, the phyllode being on either side of them. 



