SOME DESMIDS OF THE UNITED STATES. 297 
vexo et late retuso ; lobis lateralibus subinequalibus (superioribus 
majoribus) cum incisuris primariis tribus, ea mediana profundiori, 
in lobo inferiori lobulis emarginatis, in lobo superiori lobulis 
divisis eum partibus emarginatis; marginibus sinuum et incisu- 
rarum subpolarium denticulo (cire. 5) regulariter ordinatis 
intra margines ferentibus. 
Long. 116 p; lat. 1004 ; lat. apic. lob. polar. 56 p; lat. isthm. 
16 p. 
Hab. Tallahassee, Florida (H. J. no. 546). 
In the division of its lateral lobes and also in the possession of 
the small teeth bordering the margins of the sinus and subpolar 
incisions, this species most nearly approaches M. speciosa, Wolle, 
but the ultimate lobules are more numerous, emarginate and not 
sharply apiculate as in the latter species; the polar lobe is also 
quite different in form. 
Dr. Nordstedt (in letter to Johnson) expressed the opinion 
that it was nearest M. conferta, Lund., var. hamata, Wolle. We 
think, however, that the decided inequality of the superior and 
inferior lateral lobes, and the marginal denticulations of the 
median and subpolar incisions, are characters more in affinity 
with M. speciosa; moreover, the polar lobe gradually widens 
from base to apex and the latter is destitute of teeth. 
The outward form of M. tetraptera is different from that of 
either M. speciosa or M. conferta var. hamata. 
65. MICRASTERIAS FOLIACEA. Bail. in Ralfs, Brit. Desm. p.210, 
t. 95. £.3; Johnson, in Bot. Gaz. xix. p. 56, t. 6. ff. 1-4. 
Long. 80 p; lat. 85 p. 
Hab. Laconia, N.H.; rather scarce in a pond on the stream 
flowing from Lake Winnepesaukee (H. J. no. 665). 
66. M. APrcUrLATA, Menegh. 1840; Cooke, Brit. Desm. p. 186, 
Pl. 48. f. 1 (after W. B. Turner). 
Tat. 220 p. 
Hab. De Land, Florida (H. J. no. 572). 
67. M. Jounsonir, n. sp. (Pl. 16. fig. 5.) 
M. magna, circiter tam longa quam lata, profundissime 
constricta, lateralibus sinus sigmoideo-sinuatis; semicellule pro- 
unde quinquelobz, incisuris extrorsum ampliatis ; lobo polari 
"hBusto et elongato, lateribus subparallelis sed apicem versus 
divergentibus, apice late bifido, angulo unoquoque acuto et in 
"piam longam producto; lobis lateralibus subcampanulatis et 
