OF THE FAMILY BACILLARIA. 



139 



6. Gaillonella? . (PI. II, fig. 8.) Corpuscles long, cylindri- 

 cal, with two lines of constriction, adhering by alternate angles so as 

 to form long zigzag chains, and occasionally auricled. 



The curious bodies represented in PL II, fig. 8, appear to partake 

 of the characters of both Gaillonella and Bacillaria, showing the 

 cylindrical corpuscles of the former, united by alternate angles, 

 as in many species of the latter. It is perhaps, related to Diatoma 

 anritum of Lyngbye, which is described as having the " joints 

 quadrangular, rounded, with an auricle at each angle," and of 

 which GreviUe remarks that the auricular appendages of the 

 angles give to the frustules the appearance of " microscopic 

 woolpacks." Having seen no figure or specimen^of D. anritum, 

 I cannot decide as to its identity with our species ; I believe, 

 however, that ours must be different, both from its abundance 

 and from the remark of Kutzing (Linnsea, 1833, p. 585) that D. 

 auritum probably belongs to the Desmidiacea. 



Our species consists of large cylindrical siliceous joints, usually 

 adhering together by the alternate angles in a zigzag manner. Most 

 of the frustules show two fines of constriction, as shown in the 

 figure. The connection of the frustules is by a very conspicuous, 

 flexible hinge-like ligament, which often gives to the joints an 

 auricled appearance, and makes the comparison of them to " mi- 

 croscopic woolpacks," or rather bales of cotton, not inappropriate. 



The joints usually contain a yellow or ochraceous substance, 

 arranged in a stellate manner, and not unfrequently this appears 

 to be composed of minute globules, (ova ?) as shown in the figure. 

 This species occurs, in vast quantities, in the Hudson River, at 

 "West Point. It may be found in some places at low tide, giving 

 to the shores a ferruginous color in spaces even as much as a 

 hundred square yards in extent. 



7. Gaillonella ferruginea. Corpuscles very minute, convex on the 

 ends, ferruginous, oval, smooth, having the form of articulated tlii'eads, 

 often united, almost branching, .jijVTr to xtjVtj o^ ^ \vcie. 



Ehrenberg states with a mark of doubt, that it occurs in all 

 ferruginous waters ; fossil in bog iron ore ; and in the yellow 

 opal of Bifin. A copy of Ehrenberg's figure may be seen in 



