Naviculacea.] infusorial animalcules. 367 



Fkagilama (?) Stjjlidiam. — Fossil, from the same locality. 



F. Seminulum (Eht.) — Fossil, in earth frqpi Siberia. 



F. Syriaca. — Tcstules eight times longer than broad, striae wide 

 apart, ten in l-1200th. Length 1 -960th. Marine, Syria. 



F. mesodon. — Length not much greater than breadth (subquadrate), 

 centre rather turgid on the lateral aspect, ends obtuse, constricted ; 

 four strife, and teeth about the middle, only on the sides. Secondary 

 side elliptic-lanceolate, dilated at the middle, -with two to four striae. 

 Length 1- 1104th. Friburg, in Switzerland, among Conferva. 



F. Catena. — Smooth, length twice the breadth, ovate laterally. 

 Length 1-1 152nd. Mexico. 



F. acuta. — Smooth, linear, length six times the breadth ; laterally 

 cuneate, acute. Length l-576th. Among Conferva; Friburg, Switzer- 

 land. 



F. Capucina (Kiitz.) — Filaments more or less elongated, segments 

 linear, rectangular ; on secondary side acute and narrowly lanceolate. 

 Common. This plant, according to Kiitzmg, represents the species 

 named by Ehrenberg, respectively, Fragilaria rhabdosoma, multipunc- 

 tata, bq)anctata, angusta, scalar is, diojjhtJialma, and fissa. 



F. corrugata. — Segments geminate, corrugated on each side ; on 

 secondary side acutely lanceolate,^^ Length 1- 1440th. Fresh water, 

 Nordhausen. 



Kiitzing adduces this species as synonymous with F. confervoides 

 (Gre\Tlle), thus described (Hooker s British Flora, vol. ii, p. 407.) — 

 Filaments elongated, attenuated, compressed, excessively fragile, the 

 joints about as long as they are broad {i. e. considering the breadth 

 of the frustules to be that of the chain.) Streams. Tufted, two to 

 four inches in length. 



F. hj emails (Ann.- Nat. Hist., 1843, Lyngbye.) — Frustules broad, 

 puncta at the ends very minute, lateral surfaces broad, elliptic-lan- 

 ceolate, with well-marked striae, which terminate in distinct puncta 

 along the margins. Foiuid in fresh-water pools and rivulets. 

 Brownish when recent, whitish brown when dry ; filaments elongated, 

 attenuated, very fragile, separating into single frustules almost imme- 

 diately after being gathered. Mature frustules generally two or 

 three (occasionally five or six) times longer than broad. 



In Hooker's British Flora, tlu-ee other species, named, respectively. 



