On the Structure and Affinities of the Genus Siphonia

Some years ago my friend and tutor Mr. Bonney was kind enough to procure for my examination a collection of phosphatic nodules from the Gault of Folkestone, amongst which were included several specimens of what I considered to be species of Siphonia in a phosphatized condition. Knowing well, from a previous investigation of phosphatized Ventriculites from the Cambridge Greensand, how perfectly sponge-structure is sometimes preserved in this state, it occurred to me that I had here a good opportunity of determining the minute structure of this sponge and its relations to recent forms.

Accordingly I requested Mr. Cuttell, of 52 New Compton Street, Soho, to prepare a series of transparent slices from my specimens; and on examining under the microscope the beautiful sections he made for me I saw displayed, in all its details, the characteristic structure of a Lithistid sponge. I then submitted my preparations to my kind friend Mr. Carter, who not only confirmed my observations, but gave me the benefit of several valuable suggestions, and generously sent me pieces of the recent Discodermia polydiscus, Bocage, for comparison. Subsequently Mr. Vicary, with great kindness, put a large number of siliceous specimens of Siphonia from the Blackdown Greensand at my disposal, and I obtained from Mr. Bryce Wright an example of Siphonia (Hallirhoa) costata, Lamx., from the Greensand of Wiltshire. Finally my friend Mr. Moore afforded me every facility for the examination of the beautiful collection of Choanites preserved in the Liverpool Free Museum; and transparent slices taken from from specimens of that genus were sent me from the Woodwardiau Museum, Cambridge, by the courtesy of Professor Hughes.