242 On some Microscopic Fossils from the Colchester Chalk. 



Cytherella ovalis, Bairdia subdeltoidea, Cy there punctatula, and 

 Cythereis ciliata are those most usually met with both in the Col- 

 chester chalk and in the chalk of England and Europe generally. 



EXPLANATION OF PLATES VIIL, IX. 

 Plate VIII. 

 The natural size of the object accompanies each specimen. 



Figs. 1, 2, & 3. Dendropora ? 



Fig. 4. Ceriopora ; like C. tubiporacea of Goldfiiss (Petrefact. Germ.). 

 Fig. 5. Melicertes7 



Figs. 6 & 7- Pustulopora ; like P. {Ceriopora) madreporacea of Goldfuss 

 (Petrefact. Germ.). 



Fig, 8. Tragos : a 8i b, the two opposite sides ; c, highly magnified por- 

 tion. 

 Fig. 9. Manon : a Si b, two views. 

 Fig. 10. Tragos. 



All of these specimens are much worn, and do not possess suflSciently 

 well-preserved characters for e.^act identification. 



Plate IX. 

 The natiu-al size of the object accompanies each specimen. 



Fig. I. Nodosaria liinbatajD'Orhigny*. 



Fig. 2. Marginulina ensis, Reuss (fragment) : a, b, c, d, difiierent views. 



Fig. 3. elongata, D'Orb. (fragment) : a, side view ; b, the broken end. 



Pig^ 4, trilobata, D'Orb. : a, side view; b, back view; c, view of the 



outside of the last chamber, showing the aperture. 



Fig. 5. Frondicularia Verneuiliana, D'Orb. : a, b, c, different aspects. 



Fig. 6. Cristellaria rotulata, Lamarck sp. 



This species was termed Lenticulites rotulata by Lamarck; it is the 



Nummularia Comptoni of Sowerby. M. D'Orbigny recognized it as a Cris- 

 tellaria. 



Fig. 7. Rosalina marginata, Reuss; upper side. 



Fig. 8. Globigerina cretacea, D'Orb. : a, upper side ; b, imder side, the last 

 two cells each showing an aperture. The dottings on this and on 

 fig. 9 indicate the coarseness of the minute perforations. 



Fig. 9. Truncatulina Beaumontiana, D'Orb. : a, upper side ; b, under side. 



* For minute descriptions of these and other Cretaceous Foraminiferae, 

 consult a memoir by M. A. D'Orbigny in the 4th volume of the ' Memoirs 

 of the Geological Society of France ' ; and Dr. Reuss's work on the ' Fos- 

 sils of the Bohemian Chalk.' 



