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Show 348 MR. F. E. BEDDARD ON EARTHWORMS [Apr. 16, not completely ascertained ; in Polytoreutus there are no facts which prove one or the other origin for these structures. The spermatophores of Stuhlmannia are very large; the largest which I measured was fully 3 m m . in length, and it must be noted that t he diameter of the worm in which it occurred was only 2 m m . The spermatophore, therefore, has to lie longitudinally in the spermathecal sac. Text-fig. 86. Spermatophore of Stuhlmannia, greatly magnified. The form of the spermatophore is illustrated in the drawing (text-fig. 86). It is not by any means unlike a cestoid worm, for which, indeed, for a moment I mistook it. The strongly pronounced " head " and the bag-like body widening irregularly is very like the immature stage of those parasitic worms. The shape is not, however, suggestive of that of any other spermatophore with which I am acquainted, either at first hand or by descriptions. It has the length of the longest spermatophores of Polgtoreutus. but the wideness and bulk generally of the spermatophores in the |