Specimens of this species have been found at Fath Pond, north of Coffeen, Ill., in which both zygospores and aplanospores occurred in abundance. The aplanospores fill or slightly enlarge the vegetative cells as in _Z. Collinsianum_ Transeau,[C] but the ends of the spores are usually more nearly truncate, 34-50µ × 30-80µ. At Casey, Ill., a variety with the same dimensions but steel blue spores occurs in the old Ice Plant Pond. var. =caeruleum= nov. var. Cellulis vegetativis et sporis ut in typo, sed membrana media sporarum caerulea. Vegetative cells and spores as in the type, except that the median spore wall is steel blue. Type in Collection E. N. T. No. 495. =Zygnema stellinum= (Müller) Agardh. The specimen distributed under the name _Z. insigne_ (Hass.) Kütz. in the P. B.-A. No. 457, from Chestnut Hill, Mass. (G. F. Moore), belongs to this species as shown by the scattered mature spores. This species is common everywhere in central Illinois. In the U. S. Natl. Herb, is a specimen from Baltimore Co., Md., (J. D. Smith). In Amer. Alg. No. 157, a specimen from St. Paul, Minn., (J. E. Tilden) shows both zygospores and aplanospores. The aplanospores are cylindric ovoid in form, occupying the entire cell 30-33µ × 40-88µ, median wall scrobiculate. =Zygnema cylindricum= nov. sp. Cellulis vegetativis 28-33µ × 28-66µ; zygosporis incognitis; aplanosporis cylindricis vel tumido-cylindricis, 30-33µ × 24-58µ, sporangia complentibus; membrana media brunnea scrobiculata. Vegetative cells 28-33µ × 28-66µ; zygospores unknown; aplanospores cylindric or tumid-cylindric, 30-33µ × 24-58µ, filling the sporangia, median wall brown, scrobiculate. Type in Herb. E. N. T. No. 1164, 1177. This species is not uncommon in ponds, and pools throughout central Illinois. It was at first classified as aplanosporic material of _Z. stellinum_ (Müller) Agardh. On going over the specimens in all my collections, however, it was found that in no case were the filaments containing the aplanospores connected with the filaments containing zygospores. This must be the final test of the identity of the species, as it occurs in some collections alone, sometimes associated only with fruiting _Zygnema pectinatum_, and sometimes with _Z. stellinum_. =Zygnema rhynchonema= Hansg. In a collection of algae made at the Minnesota Seaside Station, Vancouver Island, B. C., in 1901, by Professor Tilden, is a form which perhaps belongs here. The vegetative cells are from 22-28µ in diameter, and 32-52µ in length, while the European specimens are described as 16-20µ in diameter and 2-6 diameters long. The Vancouver specimens are producing both aplanospores (globose, 24-26µ in diam.), and zygospores (ovoid 24-28µ × 36-44µ) by the union of gametes through the partition wall separating the two gametangia. The specimens show some evidences of being in an abnormal condition. =SPIROGYRA= Link. =S. Juergensii= Kützing.