186 FAMILY GLOBIGERINIDA. 



appearance of Sphceroidina in geological time is in the Chalk of Bohemia and Westphalia 

 (lxxxv, xc (^) ; and it occurs in various Tertiary formations, especially those of Vienna 

 and Sienna. 



Genus VII. — Carpenteria (Plate XXI). 



307. History. — The genus Ccnyenteria was established by Dr. J. E. Gray in 1858 ('Pro- 

 ceedings of the Zoological Society,' April 27) on the basis of a remarkable set of specimens 

 collected by Mr. Cuming in the Philippine seas, which had been supposed by several experienced 

 Conchologists to be sessile Cirripedia. Dr. Gray was led by his examination of them to regard 

 these organisms as a connecting link between Sponges and Foraminifera ; the shell being 

 multilocular and minutely foraminated like that of the Rotaline family of Foraminifera, whilst 

 the fleshy substance occupying its chambers is strengthened with spicules like those of 

 Sponges. — The larger number of the specimens of this type in the collection of Mr. Cuming 

 are attached to the surface of a piece of Pontes (coral) ; other specimens, however, are 

 adherent to the shells of Peden and Cardita ; and Mr. W. K. Parker has met with them on 

 the surface of other Bivalves, especially C/tama gi(/as. 



308. External Characters. — The ordinary external aspect of Carpenteria, as represented 

 in Plate XXI, figs. 6, 14 (taken from a group on the surface oi Poritcs, of which the indi- 

 viduals are in close proximity to each other), at once suggests a resemblance to the Balaniform 

 type ; the shell being conical, attached by its broad base, furnished with a single definite 

 aperture at its apex, and presenting an appearance of irregular divisions into triangular seg- 

 ments, which might easily be supposed to be "valves" bounding a single undivided cavity. On 

 breaking into the interior of the shell, however, it immediately becomes apparent that the 

 foregoing resemblance is superficial only ; the entire cavity of the shell being divided into 

 numerous chambers, which are completely separated from each other by septa, whose lines of 

 junction with the external wall (indicative of the successional additions which the shell has 

 received) give rise to the appearance of valvular divisions. And a closer examination reveals 

 that these chambers are disposed upon a spiral type, each whorl completely investing (save 

 on the adherent base) that which preceded it, so that only the external wall of the last whorl 

 is anywhere seen on the surface. In the specimen represented in fig. 7, which is one of the 

 isolated individuals occurring on the valve of a Pecteti, the shell has a much less regular form, 

 owing to the more or less complete divergence of the basal portions of the chambers of 

 the last whorl, and the partial subdivision of some of those chambers into lobes which exhibit 

 the like divergence. The shelly surface of the wall of each chamber presents a somewhat 

 areolated aspect, which depends upon its being raised into a multitude of low rounded elevations 

 (fig. 10); and under a sufficient magnifying power these areolae are seen to be pretty uniformly 

 marked with minute punctations (fig. 12, a, a). The form of the aperture at the summit of 

 the cone, of which two examples are shown in figs. 8, 9, presents a striking resemblance to 

 that of the aperture of the Milioloid Foraminifera. In some of Mr. Parker's specimens, the 

 oral ring is extended upwards into a tube or syphon at least equal in length to the radius of 

 the cone. 



