230 Rhodora [DECEMBER] 
Penium margaritaceum Bréb., in Ralfs. Brit. Desm., 1848, p. 149, 
pl. 25, fig. 1, a-c; Wood, Smithson. Contrib. to Knowl. No. 241, 1874, 
p. 107; Wolle, Desm. U. S., 1884, p. 34, pl. 5, figs. 5, 6, 11; W. & 
G. S. West, Brit. Desm., vol. 1, 1904, p. 83, pl. 8, figs. 32-35. 
Cells 7-11 times as long as wide, cylindrical, median constriction 
present, ends broadly or truncately rounded, cell wall with granules 
arranged in longitudinal rows, reddish or yellowish brown in color. 
Length 120-240 u; breadth 17-22 u; apices 12-15 y. 
Me.: Orono (Harvey), Kittery, not common! N. H.: Plymouth 
(Wests); Pudding Pond, North Conway! Intervale! Vt.: (Wolle); 
Mass.: Amherst (W. West); Lake Quinsigamond, Worcester (Stone); 
Bridgewater! Lake Watuppa, Fall River! R. L: Wainskut Pond, 
North Providence (Bailey); Conn.: (Wolle). 
This is one of our most striking species and easily noted, yet cannot 
be called common. 
* PENIUM CUTICULARE W. & G. S. West. 
Penium cuticulare W. & G. S. West, Journ. Roy. Mier. Soc., 1896, 
p. 153, pl. 4, figs. 43, 44; Brit. Desm., vol. 1, 1904, p. 85, pl. 6, figs. 4, 5. 
Cells minute, 23 times as long as wide, cylindrical, no constriction, 
ends broadly and truncately rounded, cell-wall reddish brown, minutely 
but irregularly papillose. 
Length 22 u; breadth 9.3 y. ` 
Mass.: Lake Watuppa, Fall River! 
Pentium CLeEvEI Lund., var. crassum W. & G. S. West. 
Penium Clevei Lund. Desm. Suec., 1871, p. 86, pl. 5, fig. 11; var. 
crassum W. & G. S. West, Journ. Roy. Micr. Soc., 1894, p. 4, pl. 1, 
fig. 5; Brit. Desm., vol. 1, 1904, p. 88, pl. 8, fig. 38; Cushman, Bull. 
Torrey Club, vol. 32, 1905, p. 225, pl. 7, fig. 8. 
Cells about twice as long as wide, lateral margins decidedly convex, 
slightly constricted in the middle, ends of the cell finely granulate, 
chloroplast with a single large pyrenoid. Zygospore spherical, with 
numerous broad, squarely truncated processes. 
Length 80-96 u; breadth 40-44 u; isthmus 38.5-40 p; breadth of 
zygospore with processes 68-78 u: without processes 54—57 p. 
Mass.: Pondville! 
This is the only record for the zygospore of this species. 
