Published online by Cambridge University Press: 01 May 2009
The sac-like structures occasionally found in association with graptolite rhabdosomes have always attracted the attention of palaeontologists whenever recognized. They have very generally been regarded as of reproductive character, though in some cases doubt has been held as to whether they were really attached to the rhabdosome; any specimens showing attachment beyond the possibility of doubt are therefore valuable, and in the case of the specimens now figured this attachment is particularly clear.