407 
Mr. H. J. Carter on Foraminifera. 
the fact now; and hence the absence of such spicules in the fossil 
sponge proves nothing one way or the other ; they may, or, 
just as possibly, they may not have been present in the living 
form. But while this uncertainty prevents us from placing 
the sponge just described in the same genus as Pharetro- 
spongia , we need not be deterred by a difference of so slight a 
value as that of external form, while so many and marked 
resemblances exist between the two sponges, from placing 
them very near one another in our classification ; and there is 
no reason why this approximation should not be indicated by 
a similarity in their generic names. 
EXPLANATION OF PLATE XXX. 
Fig. 1. Pharetronema zingiberis (n.gen.et sp.), f- nat. size. From a photo¬ 
graph. 
Fig. 2. Fragment of the dermal layer, x 25 diameters. 
Fig. 3. Spicular fibres of the internal network, showing their mode of 
branching and anastomosing, a, adherent sarcode containing 
flesh-spicules. X 25. 
Fig. 4. Fibres terminating in the dermal network, a, layer of arches or 
vaults formed by the curving together and junction of the 
internal fibres; b, layer of spicular pencils. X 25. 
(Figs. 5-14 all magnified 435 diameters.) 
Fig. 5. Spicide of the fibre, typical size and shape. 
Fig. 0. Similar spicule, but smaller, from the dermal layer. 
Fig. 7. Very common variety, mucronate at one end. 
Fig. 8. Straight form of typical spicule. 
Fig. 9. Flesh-spicules, one on the left straight, the other two curved. 
Fig. 10. Variety of fibre-spicule with a mucronate bud and a “ mucro- 
nated mucrone ” for a point. 
Fig. 11. Mucronate point commonly assumed by the fibre-spicules. 
Fig. 12. Conical point, also common. 
Fig. 13. Variety with a spherical head and a mucronate point. 
Fig. 14. Variety with both ends rounded off. 
Fig. 15. Longitudinal section of a branch, showing the radiate arrange¬ 
ment of the skeletal fibres (nat. size). 
The Museum, Bristol, 
Oct. 7, 1878. 
XLYI .—Notes on Foraminifera. 
By H. J. Carter, F.Ii.S.'&c. 
For the better understanding of what I am about to mention 
respecting some of the Foraminifera that I have lately de¬ 
scribed, it is desirable to premise the following brief epitome 
of their general organization and structure. 
Dujardin was the first to point out their real nature, by 
stating, in 1835, that their soft parts were composed of granu- 
