Cotylurus lutzi (Strigeidae): pre-and postadult stages cultured in vitro.

P. F. Basch, J. J. DiConza, and B. E. Johnson (J. Parasitol. 59, 319-322, 1973) reported cultivation of Cotylurus lutzi from tetracotyle to adult, with production of eggs yielding miracidia infective to snails. We have now extended in vitro cultivation to all stages from postcercaria to mother sporocyst. Biomphalaria glabrata, 12-15 mm diam, were exposed to a few dozen cercariae of C. futzi. On the following day the snails were cleaned and soaked for 3 hr in 500 units/ml penicillin G and 500 mCig/ml streptomycin sulfate in sterile distilled water, changed once. Shells were crushed and ovotestes, separated from the rest of the snails, were teased apart in sporocyst culture medium (J. J. DiConza and P. F. Basch, J. Parasitol. 60, 757-763, 1974). Postcercariae so obtained were rinsed in several changes of medium to remove host cells, and 16 organisms were transferred to a sterile 10 x 75 mm culture tube with 1.5 ml of medium. The tube was tightly stoppered and maintained at 25” & 1°C. Figures l-6 show these larvae at intervals up to 32 days, when half of them appeared to be well-formed tetracotyles. The cyst wall was still deformable by