THE MYXOBACTERIACEAE 



143 



well-developed protoplasmic connections (plasmodesmae).* The 

 development of a Volvox sphere, as Janet ^ has pointed out, is 

 comparable with the development of the embryo of animals up to 

 the blastula stage ; and, just 

 as a blastula is considered as 

 an individual organism, so also, 

 it seems to the writer, should 

 be an adult Volvox. 



The Myxobacteriaceae. — In 

 Chondromyces crocatus B. and C, 

 one of the Myxobacteriaceae, 

 the individual bacteria (Fig. 80) 

 by mass action build up an 

 aerial gelatinous branched stalk 

 or cystophore, somewhat less 

 than 1 mm. high, upon the 

 ends of which the Uving rod-Uke 

 bacteria are packed together in 

 little oval cysts (Fig. 81, no. 6, 

 and Fig. 80, C and D). These 

 cysts have definite walls, are 

 grouped together in globose 

 heads and, at first sight, appear 

 to resemble the spores of a mould 

 fungus. 3 According to Thaxter,* 

 during the formation of a cystophore (Fig. 81, nos. 1-6), a " mass 



^ The text-book illustrations always show the plasmodesmae in Volvox but not 

 in Eudorina. Eudorina is usually represented as having its cells widely separated 

 from one another by thick masses of jelly ; but, even in this organism, protoplasmic 

 strands stretch between the cells although they can be seen only after staining 

 (Fritsch, loc. cit., p. 76). 



^ C. Janet, loc. cit. 



^ Chondromyces crocatus has orange-red cystophores and straw-yellow cysts. 

 I have seen it several times in the laboratory at Winnipeg, where it has appeared on 

 old, rather wet, horse-dung cultures. It first attracted my attention in these 

 cultures as it grew on the rotting stipes of Galera bulbifera, one of the coprophilous 

 Hymenomycetes. A pure culture made by sowing cysts obtained from a dung 

 culture provided the material from which Fig. 80 was drawn. 



* R. Thaxter, " On the Myxobacteriaceae, a new order of Schizomycetes," 

 Botanical Gazette, vol. xvii, 1892, p. 396. 



Fig. 76. — Licmophora flahellata, a marine 

 colonial Diatom. The wedge-shaped 

 frustules are coherent so as to form a 

 flabellum or fan at the end of each 

 branch of a gelatinous stalk which 

 is attached to a sea-weed. From Car- 

 penter's The Microscope and its Reve- 

 lations (London, ed. IV, 1868, p. 291). 



