518 Reviews — H. Ranff — On RecepfacuUtes. 



II. — Untersuchungen ueber die Organisation und systematisghe 

 Stellxjng der Eeceptaculitiden. Von Hermann Kauff. 

 Abbandl. der k. bayer. Akadeniie der Wiss. II. cL, XVII. Bd., 

 III. Abtb. pp. 647-722, Pis. I.-VII. 



Eesearches into the Organization and Systematic Position of 

 THE Receptaculitid^. By Hermann Eauff. 



AS part of a work on tbe fossil Sponges of Germany, Dr. Eauff 

 bas critically examined tbe Palaeozoic fossils included in tbe 

 family of tbe Eeceptaculitidfe, and in tbis Meuioir be bas given a 

 more detailed description, witb fuller illustrations of tbeir structure, 

 tban bas previously been attempted. Tbe main cbaracters of tbese 

 fossils bave long been known tbrougb tbe works of Billings, 

 Giimbel, and otber writers, but nevertbeless some new and 

 interesting points, well deserving of consideration, are here brougbt 

 forward. 



It is well known to palaeontologists tbat tbe nature and relation- 

 ship of Receptaculites and its allied genera bave been fruitful subjects 

 of discussion, and tbat they bave at different times been placed in 

 various divisions of tbe plant and animal kingdoms. In 1884, 

 Hinde supported tbe view tbat they were sponges allied to the 

 siliceous bexactinellidae, on tbe ground that tbe individual elements 

 or spicules — ^Meromen, as they are styled by Dr. Eauff — of which 

 their walls are composed, very strongly resembled in general 

 features, tbe spicules of recent and fossil bexactinellid sponges, and 

 that, like tbese lattei", they must have originally been composed of 

 silica. In their present condition many of tbese fossils are of 

 granular crystalline calcite ; some, perhaps the majority of tbe 

 specimens known, are only casts, more or less replaced by iron 

 peroxide or otber substances, others are now siliceous, but tbe silica 

 in tbese is partially crystalline, and therefore not original, and 

 occasionally a rare specimen occurs which is found to be composed 

 of a finely fibrous carbonate of lime. In this latter condition there 

 are traces of concentric layers of growth, and of an internal tube or 

 canal in the vertical rays or pillars of the spicules, and this fibrous 

 structure was regarded by Giimbel as tbe original skeleton of the 

 organism ; a view upheld and defended by Eauff in tbis Memoir. 

 If tbis view is correct, all analogy with siliceous bexactinellids at 

 once falls to the ground. The fibrous calcite in these particular 

 specimens was considered by Hinde to be merely a replacement 

 after silica in tbe same way tbat granular calcite very often replaces 

 tbe silica in otber fossil sponges, but Dr. Eauff maintains tbat tbis 

 is mineralogically impossible; tbat no traces of tbe original lines of 

 growth could be preserved in spicules thus replaced ; and con- 

 sequently tbat Receptactdttes is a calcareous organism. 



Tbe question of tbe original mineral nature of tbese fossils is by 

 no means a simple one, and one would like to have clearer evidence 

 whether the fibrous carbonate of lime could possibly have resulted 

 from replacement, or whether it is primarily of organic origin, as 

 Dr. Eauff, following Giimbel, asserts it to be. There can be no 



