Naviculacea.'] inffsoeial animalcttles, 423 



STAtJRONEis Bailey i. — Broadly lanceolate, tapering gradually to 

 the ends, whicli are obtuse. Surface with very fine undulating 

 longitudinal lines; approaches S. ptcroidea and S. Phoenicenteron. 

 North America. 



S. hirostris. — Smaller, narrowly lanceolate, ends produced, ros- 

 trate, subacute. Siu'inam, Mexico. 



S. (?) constricta. — Small ; oblong ; constricted at the centre, and at 

 the ends, which are much produced and obtuse. Chili. 



S. dilatata Small, broadly oblong on ventral aspect; laterally 



straighter ; ends constricted, obtuse, broadly and briefly rostrate. 

 Mexico, Chili. (P. 15, f. 16.) 



S. fenestra. — Elliptic-oblong, with obtuse cuneate extremities ; 

 quite smooth at centre, but with marginal parallel lines. Cayenne. 



S. gracilis. — Slender ; lineai', lanceolate ; ends tapering, truncate. 

 North and South America. 



S. linealis. — Narrowly linear, oblong, ends tapering, obtuse, pro- 

 duced, and rostrate ; parallel lines on the margin. Length 1 -720th. 

 Trinidad, Nordlaausen. 



S. lineolaia. — Lanceolate, with dotted longitudinal lines ; ends 

 tapering, subacute. Cayenne. 



S. Liostauron. — Styliform, slightly turgid at centre, extremities 

 but slightly tapering and rounded. Iceland. 



S. Monogramma. — Oblong, turgid at centre; ends constricted, 

 enlarged, rounded, sub-capitate. Surinam. 



S. Pohjgramma. — Lanceolate, with dotted lines, decreasing towards 

 the ends, which are rounded and obtuse; central umbilicus expanded 

 transversely. Cuba. 



S. Phylhdes. — "Widely lanceolate or elliptic, smooth ; ends much 

 contracted, ro.strate, subacute. (P. 15, f. 7, 8 and 9.) South 

 America. 



S. (?) pteroidea. — Large ; broadly and acutely lanceolate, with 

 very minute dotted transverse lines, as if pinnulate ; ends obtuse ; 

 approaches S. Baileyi. If a Stauroptera. (?) North America. 



S. Staurophcena. — Lanceolate, smooth, slightly constricted at the 

 extremities, which are subacute. The central transverse umbilical 

 band not very distinct. Approaches S. Phoenicenteron. North 

 America. 



