Sketch of the Infusoria of the family Badllaria. 91 



3. GaiUonella distcms. (PI. 2, fig. 5.) Corpuscles cylindrical, 

 shoi't, truncate and flattened on the ends, smooth, with two pierced fur- 

 rows, always separated in the middle, -^-^ to ^V line, usually -^i-^- 



This species occurs in vast quantities in the fossil state in Eu- 

 rope. It constitutes a large portion of the slate of Bilin and Cas- 

 sel, and of the " Berghmehl" or "fossil farina" of various locali- 

 ties. It occurs in most of the specimens of American fossil in- 

 fusoria, which I have seen. It is particularly abundant in the 

 specimens from Manchester, Mass., which are chiefly composed 

 of exceedingly minute frustules of this species. It forms here, 

 a true fossil farina, almost as light as flour, and containing in a 

 cubic inch many hundred millions of these minute siliceous shells. 

 It occurs in a living state at West Point. 



4. GaiUonella varians. (PI. 2, fig. 6, a, b.) Corpuscles fiat on 

 each end, cylindrical surface smooth, ends with fine radiating lines, 

 ovaries yellow or green, y^^- to ^^ 'i^®- 



Our fig. 6, represents a species which is not uncommon in 

 ponds near West Point. The discoid surfaces of the individuals 

 show minute radiating lines quite distinctly. 



5. GaiUonella sulcata. (PI. 2, fig. 7, a, b ?) I noticed frag- 

 ments of this species two years ago in peat from a salt marsh 

 near Stonington, and among marine Algse in the same vicinity. 

 I had prepared a sketch and description of it for this memoir, 

 before I heard of the discovery of the infusorial stratum of Vir- 

 ginia. I was, therefore, agreeably surprised to find, on inspect- 

 ing specimens of the fossil infusoria from Richmond, Rappahan- 

 nock Cliff, &c., that this species was very abundant in them. A 

 careful comparison of the recent specimens from Stonington, 

 and the fossil specimens from the tertiary of Yirginia, has left no 

 doubt in my mind of their specific identity. The following is 

 the account of the recent specimens, written several months be- 

 fore the reception of the Virginia fossils. They consist of frus- 

 tules, each of which is divided by a transverse line ; the cyli7idri- 

 cal surface of each frustule has a great number of parallel lines 

 in the direction of the axis, and the ends or flat surfaces show a 

 rim having lines corresponding to those on the cylindrical surface; 

 within this rim is a diaphragm having minute radiating lines. 

 Chains of thirty or forty individuals are not unfrequent in the in- 

 fusorial earth of Richmond, particularly in the upper part of the 

 stratum. These are doubtless the "oblong cylinders" alluded to 

 by Prof. W. B. Rogers in his Report on the Geological Survey of 



