92 Messrs. W. K. Parker and T. R. Jones on the 



Foraminifers, consisting of symmetrically arranged globose cells, 

 alternately placed along the axis of the shell, and rapidly in- 

 creasing in size. These may be grouped in two sorts, — one 

 biserial {Textularia; T. globulosa, Ehrenberg), and the other 

 triserial (Verneuilina ; V. pygm(ea,Egger,STp-) : the former prevails 

 in the Chalk; and both kinds are abundant in deep seas (Red 

 Sea, &c). These present conditions very analogous to what 

 obtains in other allied forms, and, like the small and delicate 

 varieties of Bulimina, Uvigerina, Globigerina, and Rot alia (espe- 

 cially R. Beccarii in shallow water), appear to owe their origin 

 to one or other of the following conditions : — an excessive abun- 

 dance of individuals, local brackishness of shallow water, or 

 extreme and abyssal depth. Such very simply constructed forms, 

 arrested at an early stage of growth, require great care in the 

 observer who would arrange them specifically; and unless the 

 little, almost transparent shell under the microscope be turned 

 in all directions, and compared with its homomorphs in other 

 groups, no certainty can be attained to : seen in Canada-balsam 

 or other liquids, or in transparent sections of rock-specimens, 

 its nature can only be guessed at. 



Referring to I)r. Carpenter's ' Introduction to the Study of 

 Foraminifera ; (Ray Society), 1862, p. 190, &c, for an account 

 of the structure and relations of Textularia, we may state Fig. i. 

 that it is one of the most polymorphic and protean spe- ^ 

 cies of Foraminifera. Its morphology is more complex 

 than that oiNodosarina. The first four or five chambers 

 are often arranged in a flat Nautiloid spire (like that of 

 Rotalia or Opercidina) ; but this direction of the coil is 

 soon changed, and the long and more or less compressed 

 spire, with its biserial alternating chambers, is formed. 

 With an almost tendril-like freedom of growth, the spire 

 varies widely in its proportions in different varieties. 

 The nautiloid coil occurs in the flattened " Bigenerine " 

 condition of Textularia ; but here further licence is taken, 

 the shell finishing with a single series of chambers, and 

 thus presenting a Trigenerine state. This trimorphism 

 has been observed in certain individuals allied to T. 

 prcelonga, from the Gault ; for in some Gault-clays, pro- 

 bably of deep-sea origin, this variety commences with Qp^ 

 a flat spiral coil, then becomes biserial with an alterna- ^^ 

 tion of chambers (Textularian), and ends uniseriallv- Textulavia 



\ i j j unncctcns 



This Trigenerine variety occurs fossil also in the Oolite- p.$J.' 

 clays. As a useful varietal form, it deserves a distinguishing 

 name, and may be termed Textularia annectens (fig. 1). 



Textularia prcelonga, Reuss, has very often a coiled commence- 

 ment (it is figured thus in Eley's ' Geology in the Garden/ pi. 3. 



