SYSTEMATIC DESCRIPTIONS CLYPEASTRINA. 29 



Genus DISCOIDEA Gray, 1825. 



Type species. — Echinites subuculus Leske, 1778, Add. ad Klein, p. 107. 



Discoidea decorata Desor. 



Discoidca decorata Desor, 1842, Monog. des Galerites, p. 63, plate 8, figs. 1 to 3. Cotteau, 

 1897, Bol. Com. Mapa Geol. Espana, vol. 22, p. 23, plate 12, figs. 1 to 7. 



Occurring in the Cretaceous of Europe, this species is also found 

 fossil in the West Indies. 



Cretaceous, Cienfuegos, province of Santa Clara, island of Cuba. 

 Many specimens in the collection of Comisi6n del Mapa Geol6gico 

 de Espana, Madrid. 



Order EXOCYCLOIDA Jackson, 1912. 



Suborder CLYPEASTRINA Gregory, 1900. 



Key to the West Indian Fossil Genera of Clypeastrina. 



Test without lunule or marginal slits. 



Madreporic pore single, test very small and flattened Sismondia 



Madreporic pores several or many. 



Poriferous areas of petals divergent, not incurved distally Anomalanlhus 



Poriferous areas of petals more or less incurved distally. 

 Test high, or if flattened, with thickened margins; petals broad, often rounded or 



truncate at tip; auricles separate Clypeaster 



Test flat; auricles fused into one piece. 

 Petals narrow and pointed. 



Genital pores 5 Laganum 



Genital pores 4 Peronella 



Petals wide, blunt, more or less widely open at tip Echinarachnius 



Test flat, with lunules or marginal slits and notches. 



Genital pores 5 ; test tending to be heavy, and lunules (or marginal notches) wide . . Encope 

 Genital pores 4; test very flat, tending to be fragile, with lunules narrow Mellila 



Of the genera of the Clypeastrina found fossil in the West Indies, 

 the following number of species have been recognized : 



Under Sismondia there are 2 fossil species (see Key, p. 29). 



Under Anomalanlhus there is only 1 fossil species, Anomalanthus gregoryi. 



Under Clypeaster there are 19 fossil species (see Key, p. 32). 



Under Laganum there is only 1 fossil species, Laganum elongatum. 



Under Peronella there is only 1 fossil species, Peronella mirabilis, sp. nov. 



Under Echinarachnius there is only 1 fossil species, Echinarachnius sebastiani, sp. nov. 



Under Encope there are 2 fossil species (see Key, p. SO). 



Under Mellila there is only 1 fossil species. 



Family FIBULARm)^ Gray, 1855. 

 Genus SISMONDIA Desor, 1858. 



Type species. — Scutella occitana Defrance, 1827, Diet. Sci. Nat., 

 vol. 48, p. 231. 



Key to the West Indian Fossil Species of Sismondia. 



Test very flat, petals somewhat pointed at tip S. antillarum 



Test moderately high (height equals one-third of length); petals blunt, open S. anguilla 



