IG 
cylindrical segments with a wide notch between, ends obtuse smooth, 
or provided with three or four small teeth, polar lobe exserted, 
neck long, with a short, conical prominence about the middle of each 
side; the ends broad, sinuate, with two horizontal arms on each 
side, one of \vhich is long and the other short, both in the same 
direction, slightly diverging. 
Longwood Pond, Passaic Co., New Jersey. 
Cosmarium excavatum^ Nord. ; C. Kjelnianni^ Wille; C. Beckii^ 
Wille; C. Ncegeleamuriy Breb.; and 
C. PSEUDOBRooMii, n. sp. (Figs. 36 and 37). — This species is sep- 
arated from C Brooinei^ Thw., by the total absence of a central infla- 
tion. 
Frequent in ponds, Sussex Co , N. J* 
In a small vial of specimens gathered by Mr. E. Potts, of Phila- 
delphia, while exploring Harvey Lake, Luzerne County, for fresh- 
water sponges, I found the same new Alicrastcrias Nordstetiana men- 
tioned above and one new Staurasinun^ which I have named 
S. PoTTsn, n. sp. (Figs. 8 and 9) — Small, smooth; semicells in front 
view broadly elliptic, furnished on each side with three divergent pro- 
cesses, apices rounded, bearing two aculei; end view triangular, sides 
concave, angles broadly truncate and produced into two processes 
with a wide rounded sinus between; a third process from a position 
somewhat back of the sinus rises at an angle of about 40,^ thus consti- 
tuting three diverging aculei-tipped processes at each of the three 
angles. 
To the collections heretofore made by Miss Butler, at Minneapo- 
lis, I have to add three ntw names, as follows: 
Micrasierias RabenJiorsiii^ Kirch. 
Cosmarium proliiberansy var. granulatum, //. Z'^A. (Figs. 13-iS) 
Cells about one-fifth longer than broad; semicells with straight base, 
sides somewhat diverging from the basal line; superior angles nearly 
right, inferior angles obtuse; centrally inflated; seen from the vertex, 
elliptic with a swelling on each side; membrane granular. Diameter 
25-28/i. 
Separated from the typical form mainly by the rather coarsely 
granular membrane; the centra linflation is also less prominent. 
From pond a near Minneapolis, Minn. 
EUASTRUM NoRDSTETEANUM, ft. Sp* — Cells quadrangular, oblong, 
nearly twice as long as broad; semicells obscurely three-lobed; basal 
lobes broad, divided in the middle by a rounded notch into too 
lobules with tridentate or spinous ends; end lobe short, pouting, 
more or less emarginate; the two sides of apex usually inclinmg 
backward, with a subacute or rounded notch betw^een ; lateral mar- 
gins furnished with tw^o or three horizontal spines. End, transverse 
and side views rectangular, with broad, square, more or less sinuate 
ends, angles dentate. 
Frequent near Minneapolis, IVLinn. Seen occasionally in Nev^' 
Jersey also. 
Xanthidium anielopccum^ var. Minneapoliense, //. var. — A new 
form possessing the peculiarity of a fifth pair of aculei immediately 
over the central protuberance and bead-like series of granules. 
