112 DESMIDS OF THE UNITED STATES. 



Hitherto found this species in three localities only : ponds, 

 Malaga, and Bamber, N. J., and Harvey Lake, Luzerne 

 County, Pa. 



M. ringexs, Bailey. Plate XXXV, figs. 1, 2. 



Oblong, seraicells three lobed, with a series of granules in- 

 side of most of the margins ; basal lobes divided by a deep 

 notch into two spreading arms, obtuse or slightly dentate at 

 the apices; terminal lobe exserted, emarginate, extremities obtuse. 



Diameter 125-150 u. 



Obtained this species from Florida only, collected by J. D. 

 Smith. 



Section III. End lobe produced into four, more <>r less diverging, rigid, 

 processes. 



M. Amkimcana, (Klirb.) Kg. Plate XXXII, fig. 2 and Vara. 3, 5. 

 Semicells three lobed ; lateral lobes broad, cuneate, their 



margins concave, incised-serrate ; end lobe broad cuneate and 

 exserted, bipartite at the angles ; the subdivisions straight, 

 narrow, minutely dentate nt the extremities, end concave. 



Diameter 100-115 fi. ; length about one-third greater. 



The wide distribution of this species entitles it to the name 

 it bears. 



There are several varieties, the one 



Var. RECTA, W'olle (fig. 3). . Is distinct in the margin of the 

 polar lobe, which is not concave and bisected. but straight with 

 two small prominences. 



Found it in a few localities in Pennsylvania and New 

 Jersey. 



Var. Hermaxmaxa, Reinsch. (fig. 5). 



Distinct in the angular intersections and regularly serrate 

 margins. 



Collected in Florida. It is not an exact counterpart of the 

 plant described by Reinsch, but very near it. 



M. Mahabulkshw akkxsis, Hobson. Plate XXXVII, fig. 10. 

 This form stands in close relation with the preceding species 

 and varieties ; it is separated by having the lateral lobes only 

 once bisected, not twice. The margins are finely serrated. 

 Diameter 125 //., more or less. 



Ponds, New Jersey, and eastern part of Pennsylvania. 



