composed of cellulose, with a broad base flattened against the sub- 

 strate, variously tapering anteriorly to form a long or short neck 

 through which a fine protoplasmic thread extends; chloroplasts 1 

 or 2 small discs. 



Key to the Species 



1. Lorica hemispherical, with an annular 



thickening about the apical aperture L. reductum 



1. Lorica flask-shaped, globose or pyramidal, 



with an elongated, narrow neck _ 2 



2. Body of the lorica globose, flattened on the side next to the 

 substrate, the neck equal to or a little longer than the body - L. ampiillaceum 



2. Body of the lorica not globose - ^ 3 



3. Body of the lorica transversely ovate or hemispherical, the neck 



equal to the height of the body in length L. Scherffelii 



3. Body of the lorica not transversely ovate or hemispherical 4 



4. Body of the lorica triangular or funnel-shaped, flaring 



at the aperture of the neck L. macrotrachelum 



4. Body of the lorica unsymmetrically and narrowly triangular; 

 neck about % the height of the body in length; not flaring at 

 the aperture of the neck L. triangularis var. pyramidatum 



Lagynion ampullaceum ( Stokes ) Pascher 1912, p. 155 



PI. 97, Fig. 9 

 Lorica flask-shaped, the body globose, flattened against the sub- 

 strate and extending into a long neck which flares slightly at the 

 opening; 12-1 4/x wide, 18-20/x long. 



On filamentous algae, usually in acid water. Mich., Wis. 



Lagynion macrotrachelum ( Stokes ) Pascher 1912, p. 155 



PI. 97, Fig. 10 

 Lorica depressed-ovoid or trans\'ersely ovoid, flattened against 

 the substrate, extending into a rather long neck which flares slightly 

 at the opening, 10-12//, wide, 15-20fi long. 



Common on Microspora and other filamentous algae, especially 

 in soft water lakes. Mich., Wis. 



Lagynion reductum Prescott 1944, p. 363 

 PI. 97, Figs. 12, 13 



Lorica globose to conical, dark brown, with an opening surround- 

 ed by an annular thicke"ning through which a fine protoplasmic 

 thread extends; protoplast globose, chromatophore 1, lying along 

 one side of the cell; 10/a high, ll.Sju, in diameter. 



This organism reminds one of Heterolagynion Oedogonii Pascher 

 (Ber. D. D. Bot. Ges., 30, p. 157, PI. 6, Figs. 1-4, 7-19. 1912), which 

 is, however, colorless and much larger than our specimens. 



Growing on filaments of Tribonema. Wis. 



[383] 



