f . ■ 



JOURNAL 



OF THE 



ROYAL MICROSCOPICAL SOCIETY. 



FEBRUARY 1904. 



TRANSACTIONS OF THE SOCIETY. 



I. — On the Structure and Affinities of the Genus 

 Porospheera, Steinmann. 



By George J. Hinde, Ph.D. F.R.S. 



(.Read December 16th, 1003.) 

 Plates I. and IT. 



CONTEXTS. 



I. Introduction 

 II. History of the genus 



III. Mode of occurrence and zonal 



distribution 



IV. Mineral character and con- 



dition of preservation . 

 Y. Form and manner of growth 



O* 



I. Introduction. 



The genus Porospheera was established in 1878 by Dr. G. Stein- 

 mann for certain small rounded fossils widely distributed in the 

 Cretaceous rocks of this country and the Continent, which, in 18 2 'J, 

 had been named and figured by Prof. John Phillips, Millepora 

 gldbularis. Steinmann considered the fossils to be nearly allied 

 structurally to Parlceria, and he placed the genus in the family 

 Milleporida?, Moseley, thus in approximately the same systematic 

 position as that to which they had been assigned by Phillips fifty 

 years previous^. Very divergent views respecting the nature of 

 these fossils have been held by older authors, and they have been 

 referred in turn to Foraminifera, Sponges, and C} T clostomate 

 Polyzoa. Latterly, Steinmann's determination of their hydrozoal 

 characters has been accepted generally as correct, though some 

 Feb. 77th. 1904 b 



