APPENDIX. 



I. INVERTEBRATE ANIMALS. 



FORAMINIFERA. 



Mr E. Wethered has shown ('Geol. Mag.,' May 1889) that 

 forms of Girvanella (see p. 127) occur abundantly in some of the 

 Jurassic limestones of Britain. Mr Wethered has also made the 

 interesting observation that the spheres of some of the so-called 

 " pisolites " of the Jurassic series are in reality formed by the growth 

 of layers of Girvanella round a central nucleus, and are, therefore, 

 not of the nature of ordinary oolitic grains. 



Receptaculitidce (p. 170). 



The remarkable fossils which are grouped together under the 

 name of Receptaculitidce have recently formed the subject of an 

 important investigation by Herr Rauff (' Zeitschr. d. Deutschen 

 Geol. Gesellschaft,' Bd. XL.) The following are the principal 

 general conclusions at which this observer has arrived : — 



1. The Receptaculitidce are spherical or pyriform bodies, with a 

 central closed cavity, the supposed basin-shaped examples being 

 only fragments of the base. 



2. Each of the individual spicular elements forming the wall of 

 the body is composed of six parts — viz., an external plate of an 

 essentially rhombic form, four diagonally intersecting tangential 

 arms which lie immediately below the outer plate, and a radial arm 

 or pillar which springs from the centre of the outer plate on its inner 

 side, and is directed perpendicularly inwards. 



3. An upper and lower pole maybe distinguished on the exterior 



