Heintz and Pramer (1972) studying Arthrobotrys dactyloides Drechs., and Insell and Zachariah (1978) and Dowsett et al. (1977) studying Dactylaria brochopaga Drechs., have all suggested origins for a preformed reserve membrane material, or surface, necessary to accommodate the expansion of the protoplast of ring cells which occurs during the violent closure of the trapping rings produced by these fungi. While material identified by these authors may indeed fulfill the role attributed to them, we have recently identified multilaminate bodies in the cells of trapping rings which may serve as an additional source of membrane reserve material in both normal and giant ring (Tsai et al., 1975) traps of D. brochopaga; it is these we wish to bring to the reader's attention. Cultures of D. brochopaga in which the production of both normal-sized and giant ring traps are phenotypic traits were initiated on half-strength potato-carrot agar (PCA) (Anon., 1968) at 25 C. After 6 da, 7 mm diam agar plugs bearing mycelium were cut from the cultures using a sterile cork borer, and transferred to fresh PC A plates. These plates were taped shut, and incubated in the dark at 25 C for 7 da. At this time the plugs were displaced from their original r sition by rapping the plates sharply either against the palm of the hand or on the laboratory bench. It had been accidently determined that displacement induced formation of relatively large numbers of upright giant rings from that mycelium growing about what had been the circumference of the agar plugs' original position on the agar surface. For transmission electron microscopy, a modification of the procedure used by Dowsett et al. (1977) was employed. Seven-mm agar plugs bearing either normal or giant rings (or both) were cut using a sterile cork borer, trimmed to remove excess agar, and individual plugs were then placed in sterile Parr bottles. Just enough quarter-strength PC medium was added to each bottle to cover the agar plug, and the bottles were incubated at 25 C for up to 72 h. The fluid was then removed from the Parr bottles and the newly developed mycelium and the remains of the agar blocks were fixed following the procedure of Hess (1966), but modified to include Ruthenium Red stain (Luft, 1971). It had earlier been noted that new mycelium developed from plugs derived from the zone of induced giant ring formation described above, also produced giant and normal sized rings. It appears that the ring inducing factor(s) was (were) operative even in the absence of added nematodes, as were employed by Dowsett et al. (1977). The material was then dehydrated in an ethanol series, and embedded in resin (Spurr, 1969). Sections 1094