148 SKETCH or TIIK INFUSORIA 



J'ihirnbeii,' luciilions E. amis as occurrini^ among fossil infu- 

 soria fi-oin West Point. I prt-sume that our figure, which rcpre- 

 si'iits a form very common both in the recent and fossil state in 

 the United States, belongs to this species. 



2. Eunotia diodoyi. (Tl. IT, fig. 29.) Striate, carapace elongated, 

 ventral side flattened, slightly bidentate at the middle of the back, 

 nineteen stria- in j^g of a line, -^ to ^'t of a line. 



Hab. West Point, fide Ehrenberg. Probably the same as fig. 

 29, which is common both recent and fossil at West Point, and 

 elsewhere in the United States. 



3. Eunotia tetraodon. (PI. II, fig. 31.) Striate, carapace semi- 

 lunar, short, flattened or concave on the ventral side, four rounded 

 teeth on the convex back, twenty-three striie in y^^^ of a line, -^^ to 

 j'y of a line. 



Common among fossil infusoria from Manchester, Mass., and 

 West Point, N. Y. The living species occurs at West Point. 



4. Eunotia pentodon. (PI. II, fig. 32.) Striate, carapace semi -lunar, 

 short, five teeth on the convex back, twenty-three strise in -j-^^ of 

 a line. 



Fossil at Manchester, Mass. Living at West Point. 



5. Eunotia serra. (PI. II, fig. 33.) Striate, carapace linear, slightly 

 curved, twelve to thirteen rounded teeth on the convex back, nine- 

 teen strise in -j-^^ of a line, ^V ^o fV ^^ ^ li'^^- 



Our figure is from specimens found fossil in Massachusetts. 

 I have also received it from various other localities. 



I strongly suspect that the number of the teeth on the back of 

 the four last described species of Eunotia, is liable to variation, 

 and that the number of species has in consequence been made 

 too great. See remarks in Final Report on Geology of Massa- 

 chusetts, volume II, p. 310, et seq. 



6. Eunotia . (PI. II, fig. 27, a, b.) This species was found 



in water from a brackish ditch in New Jersey, which was sent to me 

 for examination by Dr. Torrey. It is concave on one side, convex 

 on the other, with a slightly elevated and widened portion in the 

 middle. It is also minutely striate. 



