NATURAL SCIENCES OF PHILADELPHIA. 227 



Length of smallest specimen 0.08 mm., breadth 0.072 mm,, width 

 0.028 mm., with the mouth 0.028 mm. broad, and 0.008 mm. wide. 

 This species is anions; the most frequent at Absecom, at Longa- 

 coming, and at Lake Hattacawanna, X. J. 



7. Trinema acinus, Dujardin. Bifflngia enchelys, Ehr. Englypka pleurostoma, 



Carter. Eitghjpka e?ic/ie/y, Wallich. 



Test ovoid, often contracted towards the narrow extremity, 

 beneath which is the circular depressed nioutli. Surface of test 

 covered with circular scales. Length of largest specimens 0.1 

 mm. long, and 0.06 broad, with the mouth 0.024 broad. The 

 smallest specimens measure 0.036 long, by 0.016 broad. 



This species is common everywiiere, small ones having been 

 found in moss in the crevices of tlie bricks of the city pavements, 

 in shaded places. The largest specimens I have found in Absecom 

 Pond. 



8. Cyphoderia margaritacea, Schlumberger. Eit gh/f ha cnrvota, Verty. Evglypha 



viargarltacea, Wallicli. Ligynis baltica, Schultz. 



Test curved jiyriform, membranous, minutely and hexagonallj-^ 

 areolated. Mouth terminal, oblique, circular. The largest speci- 

 mens measured 0.L32 mm. long, 0.06 broad, with the mouth 0.02 

 wide ; the smallest specimen was 0.108 mm. long., 0.04 broad, with 

 the mouth 0.016 wide. 



The species I found in a spring at Darby Station, near Philadel- 

 phia. 



To til is same species I suspect the following forms belong, 

 described by Ehrenberg: Difflugia Lagena, D. adunca, 1). alaba- 

 mensis, D. ampulla^ and D. uncinata. 



9. ? Corycia, Dujarrlin ; ? Paviphagus, Baily ; ? Plpwophrys scutiformis, Hertwig 



ami Lesser ; perhaps Pleuropluys cylindrica, Claparede and Laclimann. 



Test thin, hyaline, membranous, colorless, structureless, flattened 

 ovate or scutiform, with acute borders, with an acute, subacute, 

 or transverselj' obtuse fundus. Mouth small, inconspicuously 

 defined, sometimes with the appearance of a C-like lip. Pseudo- 

 pods long, filiform, acutely branching and radiant from the mouth. 

 Protoplasm clear, granular, with a large nuclear vesicle, and one 

 or more contractile vacuoles. The animal moves slowly with the 

 test erect, and it feeds on diatomes, desmids, etc. The largest 

 specimens measured were 0.1 mm. long, by 0.06 broad, and 0.02 

 wide ; tlie smallest 04 long, 0.028 broad, and 0.012 wide. 



Found in a spring at Darby Station, on the Westchester R. R., 

 Pa., and at Kirkwood Pond, on the Camden and Atlantic R. R., 

 New Jersey. 



This creature agrees well with the figures and description of 

 Plagiophrys scutiformis of Hertwig and Lesser (Archio f. 2Iik. 

 AnaL, 1874, Taf. iii., figs. ii. a, b, c), but iu size it rather accords 

 with the Plagiophrijs cylindrica of Claparede and Lachman. 



