348 



NATURAL HISTORY. 



the first it sets on its new segments as nearly complete rings, close and neat, and with the sarcode 

 even branching upwards into overlying rings, so as to thicken the early portion of the shell. But 

 whether the flat compound shell is ear-shaped, and shows a delicate concentric spire on its faces, or 

 is discoidal, with rings almost truly concentric, its sarcode only comes out at the marginal pores 

 of the last " annuli " (rings) of the shell, which, like the earlier narrow curved chambers, are usually 

 (not always) subdivided in a uniform manner, corresponding to the external openings. These are 

 abundant in the West Indies and elsewhere. Alveolina is, as it were, an Orbiculi)M rolled up on a 

 long transverse axis. They are fossil and recent. 



Orbitolites, truly concentric from its first growth, has larger chambers (segments of sarcode) 

 than Orbiculina, though some of the two kinds are distinguishable with difficulty ; it is also more free 



Fie;. 16. VARIOUS FORMS OF FORAMIXIFEKA. 



1, Prondiculana goldfussi, Reuss. Cretnceoue. Bohemia. , Spirolocnlina liadoiisis, il'f),-hiinni. Miocene. Baden, Vienna. 3, Quinaiieloeuliiia ?axorum, 

 Lamarck. Eocene. Paris. 4, Cornnspira polypyra. Reims. Oligocene. Hungary, "a, Textularia irlobifrra. Unit* (strintn, A7ici./i.' /</). Upper 

 Cretaceous. Traimstein. 6, Nortosaria spinicosta. (VOrbiiniii. Miocene. Vienna. 7, Dentalina elemins, il'Orbiinin. Miocene. Vienna. 8,Cri8tel- 

 laria rotulata, Ltimarck. Cretaceous. Bohemia. 9, Globiserina confflomeratn, Srhmirjcr. Pliocene, Kar-Xikobar. n, Rotalia bcccarii. Liiinf. 

 Pliocene. Sienna. -(.Copied from Zittel, after Reims and others.) 



to grow thick in its outer rings. Each annulus is formed by the coalescence of the peripheral crop of 

 buds, with a new stolon going off from between each pair of these new segments. This is famous as 

 being one of the common fossil Foraminifera of the white friable limestone near Paris and elsewhere 

 in N.W. France. It lives in the Australian seas, and thrives at Fiji and elsewhere. 



An immense variety of forms can be grouped, according to more or less striking alliances, 

 round the Lituola (little crozier), which is essentially an arenaceous Foraminifer, but has some allies, 

 which, without losing touch of Lituola in some resemblance or other, are as porcellanous as Miliola, 

 and others which, except for their sandiness, would belong to the hyaline or vitreous group. 



Trochammina (wheel-sand), fossil and recent, is usually a simple, flat-coiled shell, looking like 

 smooth sandy plaster. But it may be otherwise twisted, and constricted at intervals. Thus one 

 kind is called T. gordialis (Gordian knot) ; and another imitates a Rotalia. Endothyra (inside door), 

 abounding in some Carboniferous strata in various parts of the world, is arenaceous, and of many 

 forms. So also Valvulina (valve) and Textularia (plaited, Figs. 16 3 , 25, 26), are sandy, but 

 only with advancing growth. They have an alternate arrangement of chambers, but on different 

 plans. Both also often grow on with a straight or linear set of chambers, as Bic/enerina (double-kind, 

 Figs. 27, 28, a variety of Textularia}. Jlulimina (bulimus-like, Fig. 3'2), with an alternate growth, 



