i 1GEN mi vck vk 



83 



lates to Lagenidium. It differs from any of the other 

 species in being a weak faculative parasite and hav- 

 ing -in extensively branched filamentous, mycelioid 

 thallns. 



Another unidentified species has been recorded by 

 Conch ('85, p. 886, tigs. 32—84) in Oedogonium 

 which he took tn be /.. brachystomum. The thallns is 

 moid and slightly irregular, 7—10/* X 15— 20 it. The 

 ■oospores are formed in an extramatrical vesicle, 

 ami after swimming about tor a short while, encyst. 

 Within one to throe hours they emerge and become 

 motile again. In rare cases encysted spores which 

 have germinated with a tube emerge, Leaving the 

 germ tube and cyst behind. No stages of sexual re- 

 production nor oospores have heen observed.* 



L. OOPHILUM Sparrow, 1989. Mycologia 31: 531. Figs. 

 1 1 t. 



L'i'jt tin oophilum Sparrow, I.e. 



Thallns solitary or several in a host cell, irregu- 

 larly saccate, ellipsoidal, broadly Iobed or non- 

 lobed; converted holocarpically into a thin-walled 

 hyaline /oosporangium. 12—25/1 wide by 20— 10 fj. 

 long, with a short sessile or slightly prolonged exit 

 papilla, MS ,» in diameter. Zoospores grape seed- 

 shaped, laterally birlagellate. isocont, 6 X 8 /i, 

 emerging individually and maturing in a globular 

 group at the exit orifice, vesicle doulitful or un- 

 known: cystospores ■> — 1> /j. in diameter. Sexual re- 

 production unknown. 



* Since this volume went to press another species of 

 Lagenidium has been reported and described by Couch in 

 tlie e<r^s ami newly-hatched individuals of the common 

 blue crab in Virginia. It is the only known marine 

 Species of this genus and is characterized by a course, 

 branched, sparingly septate mycelium, a persistent vesi- 

 cle, and asexual resting spores. Its mycelium is very 

 similar to that of L. giganteutn, and Couch believes that 

 the two species are closely related. Unlike the latter 

 species, however, it will not prow on nutrient agar made 

 with fresh water. Its economic significance as a parasite 

 is not known, but it kills the infected epps anil young in- 

 dividuals. Parasitized eggs of tin- host can be dis- 

 tinguished from normal ones by their smaller size and 



greater opacity. 



L.CALLINECTES Comb. int.'. .lour. Elisha Mitchell Sci. 

 Sot 58: 1 58. Pis. is 1!>. 

 Thallns predominantly intramatrieal, mycelioid, coarse, 



irregularis branched, sparingly septate, thin-walled, 



S i 12.6 m i" diameter; each segment becoming a spor- 

 angium. Extramatrical emergence papilla of sporangium 



tubular. II — .'9 (i / -'.') — 70 ft; protoplasm emerging as 

 an irregular, subspherical or spherical mass, up to 100 m 



in diameter, and becoming enveloped DJ 8 persistent. 

 thick, gelatinous envelope or vesicular membrane; cleav- 

 ing into zoospores as in Pythium. /oospores swarming ill 

 persistent vesicle and later liberated by its rupture: 

 tapering at the anterior and rounded at the posterior 



end, !».'i ■ i-'-<i ft, with a diagonal groove; containing 



several oil globules; isoeont ( • ) , Bagella inserted later- 

 ally (?) in groove and extending in opposite directions in 

 swimming; zoospores coming to rest and encysting, cys- 

 tospores Oblong or subspherical. 10 I I .if ft; linuiopla- 



netie. Resting spores asexual, spherical, subspherical or 



oval, ih — 30 ft, with a :i m thick wall; containing pale 



whitish protoplasm and an exceutric mass of oil globules; 

 germination unknown. 



Parasitic in the eggs and new Iv -hatch, d individuals of 

 Callinectea tap i'</».< in Virginia, (J. S. A. 



Parasitic in rotifer eggs and embryos, Huron 

 River, Ann Arbor, Michigan. 



Inasmuch as its sexual reproduction is unknown, 

 tin- validity of this species is questionable. Sparrow 

 was doubtful about its identity, as is indicated by 

 tin' two names proposed above, lie stressed the 

 similarity of its unicellular vegetative thallus to 



those of Myzocytium soophthorum, L. Oedogonii, 

 and Lagena radicicola, particularly when the lat- 

 ter's thalli are reduced. His suggestion of including 

 this species in Lagena because of its unicellular 

 thallus is not of much merit in light of Truseott's 

 ('33) earlier observations that the thallus of I.. 

 radicicola may be greatly elongate, tubular and 

 branched. Obviously size and shape of thallus in 

 this group of fungi are not always fundamental 

 diagnostic characters. It may be noted further that 

 /.. oophilum also resembles L. pi/gmacum in zoo- 

 spore size as well as in shape and size of thallus 

 ( Karling, ll). Cross inoculation experiments in- 

 volving the respective hosts of these two species may 

 possibly show that they are identical. Sparrow made 

 no attempt to grow his species on any hosts but 

 rotifers. 



The irregular, stout, 3-8 p. in diameter, branched 

 thallus which Sparrow ('36, pi. 17, figs. 13-15) 

 previously found in cysts of Euglena resembles that 

 of Lagenidium and may possibly relate to this genus. 

 Elliptical, 10 X 13 /a, thick-walled resting spores 

 were also observed in association with empty thalli. 

 Sparrow also believed that the irregular, immature 

 thallus (pi. 19, fig. 16a) which he found in a dead 

 nematode may belong in this genus. 



In this connection it may be noted that Decken- 

 bach (03) found a marine species of Lagenidium 

 at Balaclawa which parasitizes Chaetomorpha 

 aerea. However, he did not describe or diagnose it 

 and merely stated that it differs from the then known 

 freshwater species by its large size. 



Two additional species of Lagenidium (?) were 

 reported by Sehcrffel ( '2(i, p. 216) in Oedogonium 

 frankliniana and I'enium digitus but he did not iden- 

 tify tliini. 



MYZOCYTIUM 



Schenk, 1858. Uber das Vorkommen Contrac- 

 tilcr Zellen im l'Hanzenreieli, Wurzburg, 

 p. 10. 



Bicricwm Sorokin, 188.3. Arch. Bot. Nord 

 France 2 : 43. 



i PLATES 21, 22) 



Thallus intramatrieal. holocarpic; unbranched, 

 usually elongate, cylindrical and continuous when 

 young, later becoming septate and constricted; oc- 

 casionally reduced to one or two segments and be- 

 calming Olpidium-like. Zoosporangia formed di- 

 rectly from the segments of the thallus. oval, ellip- 

 soid, spherical, elongate and cylindrical, hyaline 



