852 



SYSTEMATIC HISTORY OF THE INFUSOBIA. 



Istlimia, marked by transverse rows of I ERBA. 1844, p. 83. 

 very minute cellules. Oran, Africa, | frag-ment 1-216". 



Diameter of largest 



Genus HYDEOSERA (Wallich). — Emstules quadrate, united into fila- 

 ments, and furnished with conspicuoiLS horizontal bands or septa; valves 

 cellulose, compressed, or triangular, with internal septa, and, on one side only, 

 with minute, aperture-like appendages. Marine. Filaments elongated, 

 attached, compressed, or prismatic. Joints rectangular, connected at the 

 angles by mucoiLS cushions, and marked by bands passing across the valves 

 and connecting zone. In the lateral \^ew the ends or angles are separated 

 by septa. Hydi'osera seems allied on the one hand to the Terpsinoeae, and on 

 the other to the Biddulphiese and Anguliferese. 



Hydboseba compressa (Wallich). — 

 Filaments compressed; valve oblong, 

 divided into three inflated compartments 

 by two transverse septa. Wallich, MJ. 

 vi. p. 252, pi. 13. f. 7-11. East Indies. 

 Side view with blank angles, occasionally 

 furnished with a few minute spines. 

 (VI. 8.) 



H. triqudra (Wallich). — Filaments 



triquetrous ; valves triangular, with the 

 subcircular centre di-^ided from the ob- 

 tuse, somewliat produced angles by 

 septa. Wallich MJ. vi. p. 251, pi. 13. 

 f. 1-6. East Indies. Front ^iew with 

 fom* transverse bands ; valves with un- 

 dulated sides, reticidated, except at the 

 angles, which are furnished with a few 

 extremely minute spines (vi. 13.) 



FAMILY XL— ANGULIFERE^. 



Frustules cellulose or granulate ; in lateral view angular. This family is 

 closely allied to Biddulphieoe (and in some manner connected with the Cosci- 

 nodisce^ and Eupodisceee). As in that family, the lateral portions are seen, in 

 the front view, having the central portion lil^e a band between them. Hence, 

 in order to determine their proper family, it is frequently necessary to see 

 them laterally. The angles, however, in the front view are usually less 

 elongated, and the intervening margin less lobed in the AnguHferese than in 

 the Biddulphiese. 



Genus EUODIA, n. g. (Bailey, MS.). — Frustules cellulose or granulate ; 

 in lateral view lunate. Eiiodia agrees with the Eunotieae in the shape of its 

 frustules, which can scarcely be called angular ; yet, notwithstanding that 

 resemblance in form, its punctate or granulate surface induces us to place 

 it here. 



EuoDiA gibha (Bai. MS.). — Frustules 

 in lateral view semilunate, the ends 

 somewhat conical, the lower margin 

 gibbose ; surface with radiating series of 

 minute granides. Recent. Gulf Stream, 

 (vni. 22.) From a drawing by Pro- 

 fessor Bailey. The upper margin is very 

 convex, the lower one less so. A con- 

 traction near the obtuse ends makes 

 them appear somewhat produced and 

 conical. Professor Bailey represents the 

 cross section as cuneate. Goniothecium 

 ammlis, EM. t. 33. 18. f. 4, gi-eatly re- 



sembles this species, and may be iden- 

 tical. The upper margin, however, is 

 represented as more convex, the ends less 

 produced, and the gTanules larger and 

 less numerous. 



E. ? BriglihceUii. — Frustules semilu- 

 nate, ends scarcely produced, lower 

 margin concave ; granules somewhat 

 concentric. = Triccratium semicircidare, 

 Bri MJ. i. p. 252, pi. 4. f. 21. Bermuda 

 earth. T. ohtusum, EM. pi. 18. f. 49, 

 may probabl}^ be referred to this species. 



Genus HEMIDISCUS (Wallich). — Frustules free ; valves cellulose, arcuate, 

 with a ventral marginal nodule; cellulation hexagonal, radiate. Marine. 

 We doubt whether Hemidiscus be distinct from Euodia, since the only di- 



