882 DESCRIPTION OF \Tolygastnca. 



Xiitzing's desmption is rather diflPerent from the foregoing; " Bacilli 

 oblong, tubular, adnate, ultimately connected only by a narrow 

 link (isthmus) ; with two constant longitudinal mttce, interrupted 

 in the middle, and more or less cui-ved." It is a member of his 

 family Talellariece ; tribe Vittatos. 



Geammatophoka Africana. = Navimla Africana, (Ehr.) — Dor- 

 sally square or oblong ; laterally navicular and obtuse. Internal 

 folds three m each half and undidated. Fossil in the chalk marl of 

 Oran ; alive ia sea water, at Tjom. The contents are brownish, car 

 golden-yellow-coloured, filling the whole of the iaterior, and only 

 leaving a bright transverse band just where the transverse line 

 crosses. Length 1 -2300th. to 1 -480th. 



G. angulosa. — Yiewed dorsally, square or oblong; on the side, 

 navicular and obtuse ; iatemal fold having many acute angles, 

 (plicate) ; this species may be only a variety of the preceding It is 

 colourless. Fossil in the chalk marl of Oran. Length, fossil 1-9 10th. ; 

 living, Ml 50th. 



G. Mexicana. — Yiewed dorsally, quadrangular; on the side, linear, 

 obtuse, the roimded ends being suddenly constricted. Internal folds 

 straight in the middle, uncinate at the extremity. Isthmi tumid. 

 Alive in sea water, at Yera Cruz, Naples, and Gaeta. Length 

 l-960th., little more than twice the breadth. 



G. oceanica. — Dorsally quadrangular; on the side, navicular or 

 linear, obtuse ; ends gradually attenuated ; internal folds straight in 

 the middle, uncinate towards the ends; isthmi slender; ossil in 

 the chalk marl of Oran ; alive in the Cattegat, &c. This creature 

 forms long zig-zag bands, which are fi:sed by mucus to Algae and 

 SertularisD. Dr. Elirenberg saw some frustules fourteen times 

 longer than broad, and others nearly square ; granular contents 

 yellow or reddish- brown. Length, fossil l-720th. ; living, l-2300th. 

 to l-360th, (P. 14, f. 52, 53.) 



G. undulata. — Dorsally quadi-angular ; laterally linear, with several 

 undulations ; internal folds undulated. Colom-less. Alive, Yera 

 Cruz. Fossil, Greek marl. Length l-860th. Breadth a third to 

 ODe-half. 



G. (fibba, — Quadrangular dorsally ; striated transversely on 



