ENTO MOP HT HO RALES (ANCYLISTES) 1071 



mid wall, forms an external hypha 3-6.8 u. thick which grows through 

 the water for some distance until it comes in contact with a new sus- 

 ceptible host cell; the protoplasm always in distal part of hypha and 

 closed off from empty part by one or more cross walls. If the desmid is 

 at the surface of the water the exit tubes form conidiophores, each 

 unbranched and with a single apical spherical conidium; conidiophore 

 stalk usually 25-100 (j. long, sometimes longer, about 8 [jl thick at its 

 thickest point slightly below the conidium; conidia spherical, 16-25 (j. 

 thick, with a conical apiculus; forcibly discharged by the sudden out- 

 pushing of the apiculus; conidiophore with a distinct cone-shaped col- 

 umella and quickly disintegrating after discharge of the conidia. Zygotes 

 formed within the host, usually in a row in the center, between the 

 several longitudinal hyphae and apparently by conjugation of two cells 

 of opposite filaments, with the zygote in the conjugation tube; spherical 

 or subspherical from pressure, 19-26 \x thick, the largest seen being 

 25 x 29.4 [j.; wall about 2.5 jj. thick, smooth; when mature with one 

 large, slightly eccentric shiny globule embedded in the cytoplasm" 

 (Couch, he. cit.). 



In Netrium digitus, Couch (loc. cit.), (Michigan), United States. 



"This species is easily distinguished from others by the club-shaped 

 exit hyphae, the position of the zygotes in the center of the host cell and 

 bounded laterally by the empty filaments of the parasite, the larger size 

 of the conidia and zygotes, and finally by its occurrence in Natrium" 

 (Couch, op. cit., p. 132). 



Ancylistes netrii is very common in certain bogs in Northern Michigan. 



IMPERFECTLY KNOWN SPECIES OF ANCYLISTES 



? Ancylistes sp., Canter 

 Trans. Brit. Mycol. Soc, 32: 167, figs. 4-6. 1949 

 "The intramatrical mycelium is unbranched, often extending to the 

 length of the host cell, 98-1 15 u. long by 10-17 ja. broad with rounded 

 ends and containing regularly arranged refractive granules. More than 

 one infection may occur in a single host cell. At maturity, the thallus is 

 cut up into three to twelve segments, 9-25 \i long by 10-17 \i broad. 

 Each segment produces one external hypha which grows rapidly, form- 

 ing septa posteriorly and contains highly refractive granules collected 



