Prof. Nicholson — Progress in Palceontology. 7 



The Protozoan Group of the Badiolaria has been recently shown 

 to have a much wider range in time than had been previously 

 imagined, examples of it having been lately detected in the Carboni- 

 ferous Limestone of Cheshire. These old types are apparently 

 identical with the existing Polycystina, and their tests are siliceous. 

 We must not, however, altogether lose sight of the possibility, 

 though a very remote one, that these siliceous shells were primitively 

 calcareous, and that they have simply undergone silicification. If 

 this were really the case, we should have to believe that there 

 existed in the Carboniferous seas a group of Ehizopods possessing 

 shells similar to those of the recent Polycystina in shajie, but 

 composed of lime instead of flint. 



As regards the fossil forms of Foraminifera our knowledge has 

 been greatly increased of late years by the researches of H. B. 

 Brady, Eupert Jones, Terquem, Hantken, and other well-known 

 workers in this difficult field. Unquestionably the most important 

 accession to the literature of this subject is Mr. Brady's masterly 

 '•'Monograph of Carboniferous and Permian Foraminifera (the genus 

 Fusulina excepted)," published in 1876 by the Palgeoutographical 

 Society. Among special discoveries in this department the first 

 place must be accorded to the detection by Mr. Brady of the living 

 arenaceous genus Saccammina in the Carboniferous, and to the 

 discovery by the same distinguished observer that the pre-eminently 

 Tertiary family of the Nummulinida is represented in deposits as old 

 as the Carboniferous by no less than three generic types {Archmdiscus, 

 Ampliistegina, and Nummulina itself). 



Much light has recently been thrown upon the structure and 

 affinities of many of the fossil corals, not only by the extension to 

 this puzzling group of petrefactions of the microscopic methods of 

 research, but also by late zoological discoveries. Thus, Mr. Moseley 

 has shown that the great reef-building genus Millepora, so abundant 

 at the present day, and extending backwards into the Tertiary period, 

 is truly referable to the class Hydrozoa, and not to the Actinozoa, in 

 which it had been previously placed ; whilst the genus Stylaster and 

 its allies are also truly Hydrozoal. We are thus introducied to a new 

 subclass of Hydrozoa — the Rydrocorallince — which possessed the 

 power of building up a calcareous skeleton, and we may expect to 

 find that these coralligenous Hydrozoa have played a more important 

 part in past time than has hitherto been suspected. Again, Mr. 

 Moseley has demonstrated that the living genus Heliopora, formerly 

 placed with the Zoantharian division of Actinozoa, in the old group 

 of " Tabulate Corals," is really a genuine Alcyonarian, and is there- 

 fore truly most nearly related to the living Red Coral, Sea Shrubs, 

 Organ-pipe Corals, etc. This important discovery at once shows us 

 the true position of a number of ancient types of Corals, such as 

 Heliolites, Flasmopora, Polytremacis, etc., which are fundamentally 

 most closely allied to Heliopora. Thus the Alcyonaria, previously 

 unknown in deposits older than the Secondary, are shown to have 

 commenced their existence at any rate in the Lower Silurian period. 

 The discoveries just referred to, in fact, together with the parallel 



