472 AQUATIC PHYCOMYCETES 



In Triaena, Germany. 



No description of the fungus occurs in Zopf 's text, and a formal de- 

 scription was first given by Fischer (1892: 135). 



An estimation of the sizes of the parts, arrived at by using as a meas- 

 ure the zoospore of Rhizophydium carpophilum, which is described as 

 4-5 u. in diameter and is drawn to the same magnification, indicates 

 that the sporangia of Cladochytrium polystomum are 15-20 \l in diameter, 

 the zoospores 3-4 \i, and the broadest part of the vegetative system 3 \x. 

 This agrees well with the sizes of these parts in Karling's C. replicatum. 

 Hence, save for the occurrence of several discharge tubes and the lack 

 of proliferated sporangia, Zopf 's fungus appears nearly identical with 

 Karling's. The multiplicity of tubes is not unknown in C. replicatum and 

 may have been due in Zopf's fungus to poor environmental conditions. 

 Karling's name, however, is preferred, since the organism has been more 

 completely described by him. 



Shell-boring "Cladochytria" 



Zebrowski (1936) and Porter and Zebrowski (1937) described from 

 bits of calcareous Australian sand of uncertain geological age, presum- 

 ably from Cambrian to Recent, a number of so-called "lime-loving" 

 fungi which are believed to be members of the Cladochytriaceae. 

 Through the kindness of Mr. Zebrowski a number of slides of these 

 sands have been examined. As the photographs accompanying his paper 

 clearly indicate, the bits of shell have been bored through by some 

 organism that has a saclike enlargement from which radiate delicate 

 rhizoidal canals. These sacs, presumed to be sporangia, empty to the 

 outside of the shell by a tube. In certain instances, as for example in 

 Dodgella priscus, which was found in shells and also in spicules of cal- 

 careous sponges, sporelike structures were observed in the sacs. Such 

 "spores" were also found imbedded in cavities of varying depth on the 

 outer surface of bits of shells. As Zebrowski supposes, it is possible 

 that they secrete a substance which allows them to penetrate or burrow 

 into the matrix. Indeed, it is necessary that they secrete some lime- 



