210 PROCEEDINGS OF THE COTTESWOLD CLUB 



Both divisions of the Foraminifera, i.e., \}pi^ Impcrforata 

 and the Perforata, are found in chalk. The most numerous 

 forms belong to the latter division : Globigerina, Rotalia, 

 Textularia (Plate A, figs. 8, 9, 15), and Gristellaria may 

 be mentioned as exceptionally plentiful. Trochavnnina, 

 Quinqueloculina, and one or two others, belong to the 

 Imperforaia . " 



Altogether about 40 genera of Foraminifera have been 

 detected in the Chalk. Many of the forms, such as 

 Globigerina, Rotalia, Buliuiina (Plate A, figs. 3-5), Cris- 

 tellaria, Truncatulina, Textularia, Ouinqtieloculi7ia, ' etc., 

 are not to be distinguished from their living analogues : this 

 was one of the reasons which led Sir Wyville Thompson 

 and Dr. Carpenter to promulgate their theory of the con- 

 tinuity of the Chalk. Occasionally I have found among 

 the other forms portions of shells which appear to be 

 composed of grains of sand, or other granular matter, 

 agglutinated together : they would seem to belong to the 

 arenaceous Foraminifera. Further I may mention one 

 singular form to which I am unable to assign a place. It 

 consists of a spherical cell covered with spines of con- 

 siderable length, as compared with the size of the organism ; 

 and, from what I take to be the base of the cell, 

 a long, slightly curved stem proceeds — its extremity 

 appears to be broken off. The mouth is at the apex, 

 upon the summit of an obtuse, conical elevation. The 

 whole very much resembles an apple with a long stalk, 

 covered with spines, the mouth taking the place of the 

 apple's eye (see Plate A, fig. i.) 



The next in importance of the microscopic organisms 

 of the chalk are the sponge spicules, which are both 



* The Foraminifera ai'c placed in the divisions Impetforala and Perfoyala on 

 account of the structure of their shells: those of the former are white, opaque and not 

 traversed hy canals, or tubules ; while those of the latter are more or less transparent, or 

 more correctly translucent, and traversed by canals or tubules, through which the 

 pseudopodia are protruded. 



