Myxococcus is not entirely satisfactory. A careful comparative study of many strains under a variety of cultural conditions is necessary in order to determine the validity of the morphological criteria currently em- ployed for the delimitation of species. The three species described below may merit recognition pending exhaustive study of the whole genus: 1. Myxococcus albiis Finck, 1950. (Arch, f. Mikrobiol., 15, 1950, 382.) al'bus. L. adj. albus white. Vegetative cells: Rods approximately 1.2 by 6.5 to 9.1 microns. Fruiting bodies: Dimensions not given. Roundish to lengthened, sometimes con- fluent, white to beige in color. Rapidly deli- quescing at 30° C. to slime masses with the appearance of oil drops. Microcysts spher- ical, 2.0 to 2.5 microns in diameter. Source: Isolated from soil from German}'. Habitat: Found on decaying organic mat- ter in soil. Comments: Appears to be clearly distin- guishable from the white variety of Myxo- coccus fulvus on the basis of the size of mi- crocysts. Possibly a non-pigmented variety of M. virescens or M. xanthus. 2. Myxococcus vipenis Finck, 1950. (Arch, f. Mikrobiol., 15, 1950, 383.) vi'pe.rus. L. noun vipera viper, snake; M.L. adj. vipenis pertaining to a viper. Vegetative cells: Rods 1.0 to 1.3 by 6.5 to 7.8 microns. Rod masses greenish j'ellow, becoming red on exposure to light. Fruiting bodies: Dimensions not given. Convoluted or club-shaped, mesenteric, yellow to copper-red in color. Microcysts spherical, 2 microns in diameter. Source: Isolated from soil from Germany. Habitat: Found on decaying organic mat- ter in soil. Comments: Possibly a variet}' of Myxo- coccus virescens. 3. Myxococcus brevipes Finck, 1950. (Arch, f. Mikrobiol., 15, 1950, 384.) bre'vi.pes. L. adj. brevis short; L. noun pes foot; M.L. adj. brevipes short-footed. Vegetative cells: Rods 1.0 by 6.5 to 8.0 microns. Fruiting bodies: Pale red to bright red, generally raised from the substrate on a colorless foot of slime. Deliquescent. Micro- cysts irregular, mostly spherical, 1.3 to 1.8 microns in diameter. Source: Isolated from the dung of her- bivores from German}-. Habitat: Found in the dung of various animals. Genus II. Chondrococcus* JoAn, 192^. (Jahn, Beitrage zur bot. Protistologie. I, Die Polyangiden. Geb. Borntraeger, Leipzig, 1924. 85; not Chondrococcus Kutzing, Botanische Zeitung, 5, 1847, 23.) Chon.dro.coc'cus. Gr. noun chondrus cartilage; Gr. noun coccus a berry, sphere; M.L. mas.n. Chondrococcus cartilaginous sphere. Spores embedded in a viscous slime which hardens. Fruiting bodies divided by joints or constrictions, often branched, usually relatively small. This genus is a segregate from Myxococcus Thaxter. Seven species are included, of which the first described by Thaxter and the best described, Chondrococcus coralloides (Thaxter) Jahn, has subsequently been designated as the type by Buchanan (Manual, 4th ed., 1934, 614). The first species listed by Jahn is regarded as doubtful and should not be regarded as the type for there is no evidence that Jahn ever saw the species. The type species is Chondrococcus coralloides (Thaxter) Jahn.
- In spite of the fact that Chondrococcus Jahn appears to be an illegitimate homonym
of the algal genus Chondrococcus Kiitzing, the former name is retained in this edition be- cause of general usage and because Chondrococcus Kiitzing is not, so far as has been deter- mined, in current use by algologists.
