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Show 342 MR. P. E. BEDDARD ON EARTHWORMS [Apr. 16, spermatophores of Tubifex and some of its allies are motile. Many observers have noted this fact. Thus one of the first, if not the first, to note the point, Jules d'Udekem l, remarked that " ils font quelquefois plusieurs circouvolutions." Before him Budge 2 had described these structures in Tubifex or in Limnodrilus; and though stating that they bear " cilia " (which are of course the ends of the individual spermatozoa) did not comment upon their motility as a whole. Gegenbaur in his 'Gruudziige' records the movement of these spermatophores. Claparede 3 observed that "ils agitent ieurs cils longs a la mauiere des l)icyema, mais ne cbangent que peu de place. Leur pouvoir de locomotion parait assez linrite." O n the other hand, iu Psammoryctes umbellifer (or P. barbatus as it apparently should be properly called) Lankester 4 noted a movement of great rapidity which resulted in the description of " a figure of eight passing and repassing on the same track." Tbe enormous quantity of the spermatophores within the spermathecal sac is very noteworthy and a difficult fact to understand. It must be borne in mind, however, that Polytoreutus produces a considerable quantity of eggs, while the Tubificidae, in whose spermatheca? there is but room for a few spermatophores, have large-yolked and few eggs. Text-fig. 85. Spermatophores of Polytoreutus magilensis, greatly magnified. A, fully mature spermatophore; B, an empty case. M y original drawings of- the spermatophores of Polytoreutus magilensis do not do entire justice to their remarkable form in that species, though the sketch given is quite an accurate representation of a spermatophere. I therefore exhibit some sketches (text-fig. 85) which will enable the spermatophores of the two species 1 " Histoire naturelle du Tubifex des Buisseaux," Mem. cour. et Mem. des Sav. ctrang. Acad. Belg. xxvi. p. 26. 2" Ueber die Geschlechtsorgane von Tubifex rivulorum," Arch. f. Naturg. xvi 1850, p. 7. 3 Loc. cit. 4 Loc. cit. |