THE TANGANYIKA PROBLEM. 
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and had no buds. In such forms, however, sexual elements 
were already being developed in the manubrium walls. 
Still later in the season the budding process came gradually 
to an end, the lake swarmed with jelly fishes, and a large 
proportion of them were still almost destitute of any manu- 
brium at all ; but at the same time an increasing proportion 
were becoming completely manubriated and sexual. On 
my first expedition to Tanganyika this was as far as I 
Fig. 6. — Still older asexual bud, showing 
succeeding generation of asexual buds upon 
the manubrium, a portion of which has 
already been shed, X 3J. 
could carry the life cycle, but on the second I picked the 
story up again, finding that during September and October 
the manubriated individuals gradually disappeared, the 
manubriums being gradually re-formed, while sexually 
mature individuals now swarmed. The ova and spermatozoa 
were evacuated, and later I found numbers of small planulse 
and small medusae which were growing rapidly ; but these 
showed no tendency to form buds during the autumn, and 
had, without doubt, been formed from the fertilised ova of 
the sexual forms. There thus appears to be a distinctive 
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