Navicvlacea.'] infusorial animalcules. 437 



RsAPHONEis amphiceros == Cocconeis amphiccros (1840.) — Lanceo- 

 late, length three times the width, apices styliform ; striae transverse, 

 granular, slender, 18 to 20 in 1-1 200th. Length 1-5 76th. Cux- 

 haven, Virginia, Maryland. 



E. Fmus. — Slender, linear lanceolate, four-and-a-half times longer 

 than broad ; apices styliform ; striae granular, slender, transverse, 1 7 

 to 18 in l-1200th. Length l-720th. Petersburg in Vii'ginia. 

 Approaches very near to Fragilaria Amphiceros, but differs by the 

 median suture. 



E. Leptoceros = Cocconeis Leptoceros. — Long, lanceolate, quad- 

 rangular or rhomboid ; length three times the breadth ; apices 

 styliform, long, gradually tapering; striae granular, transverse, 

 slender, generally 18 in l-1200th. Length 1 -720th. Yirginia. 



E. gemmifera. — Large, elongate, lanceolate ; length exceeding the 

 breadth three-and-a-half times ; apices long, gradually attenuate ; 

 striae, very strongly granular or pearly; 10 in l-1200th. Length 

 l-300th. Maryland. 



E. pretiosa. — Large, widely lanceolate, rhomboid ; length twice 

 the width, apices tapering gradually into a beak ; striae strongly 

 granular, the granules looking like rows of pearls, 11 in 1- 1200th. 

 Length 1 -480th. Maryland. 



Ti. JthomhHS= Cocconeis lihombus (1840). — Small; widely lanceo- 

 late, rhomboid, sometimes sub-orbicular ; length rather greater than 

 the breadth ; apices rostrate ; striae short, slender, granular, 20 to 2 1 

 in l-1200th. Length l-1152nd to l-864th. Cuxhaven and Vir- 

 ginia. 



E. scalaris. — Slender, lanceolate, acute at each end, with a double 

 row of pinnules and intervening clear spaces (fenestrae) 9 in l-1200th. 

 Diameter 1 -960th. Bermuda. 



E. fasciolata. — Large, elliptic-lanceolate ; length double the 

 breadth; striae fasciculate, minutely granular, strong, 7 to 8 in 

 1-1 200th. Length 1 -432nd. Antarctic Ocean. 



E. Scuiellum. — Slender, elliptic; one third longer than broad, 

 with strong toothed (crenulate) striae, 12 to 13 in 1-1 200th. Length 

 l-864th. Antarctic Ocean. 



Genus Ehizonotia (Ehr.) — Lorica bivalve, with two central aper- 

 tures, with the character and form of Amphora, but by longitudinal 



