NdvicilldCCa'] INFUSORIAL ANIAIALCITLES. 455 



cliaraotcrizod by tlio angular figure of its genera ; which, too, are 

 all marine. 



Amphiteteas mitediluviana. — Minute, cubical, cellulose, (reticu- 

 lated) ; lateral surfaces radiated ; angles either obtuse, or prolonged, 

 and hence the sides also straight, orcui'ved. Li-s-ing on the sea coast 

 of Denmark, England, Jamaica, &c. ; fossil in the chalk marl of Oran 

 and Greece. Diameter l-850th to l-430th. (P. 14, f. 21, 22.) 



Individual loricai (fi'ustules) unite, sometimes as many as thirty 

 together, in a filamentary fonn ; and in a recent state exhibit a brown 

 colour. " On a lateral \dew the figure is quadrangular, "sWth concave 

 sides, and at each angle there is either a roimd opening, or a large 

 and more strongly marked cell, which presents the appearance of 

 one. The central portion is four-sided, and its reticulations, which 

 are smaller, are frequently arranged in lines. Mrs. Gritfith aptly 

 compares the figiu'cs of the separated fi'ustules to bales of cloth 

 made up with bands for exportation." (Ralfs.) 



A. parallela. — Testules quadrate, with straight sides, and 

 obtuse angles ; the cells on the side disposed in parellel straight 

 lines; apertures of the angles obscure. Diameter 1-1 44th. Found 

 in Greek marl. 



Genus Bid DULPHiA, (Gray,) — Filaments attached, frustulcs siliceous, 

 quadrilateral, minutely reticulated, cohering by their alternate 

 angles, and thus forming a zig-zag chain ; the angles are equal and 

 elongated into tooth-like projections, (horns, Ehr.) 



Biddulphia, like Isthmia, has reticulated turgid frustules, which 

 cohere by the elongatad angles. It has also the lateral portions so 

 inflated, that they seem a part of the fi'ont of the frustule, the central 

 portion appearing like a band between them. The mode of growth 

 in this genus is also simUar, but it differs in having all the angles 

 elongated and equal. At fii'st the ii'ustules are connected to each 

 other by the adjoining angles. 



The generic characters are borrowed from Mr. Ralfs, (Ann. Nat. 

 Hist. vol. xii. 1843,) not having met with the paper of Ehreuberg 

 detailing them. 



This genus gives name to the family Biddulphia, of Kiitzing, in 

 which it is associated with Isthmia, Odontdla, (Kiitz.) and Zi/goceros. 



