318 Mr. TI. J. Carter on Squainuliiia scopula, 



to the purpose ot" nutrition and for the tornuition of its test 

 respeetively. 



lieturning, now, to tlic pseudo-sc})tal division of the pedestal, 

 K't us consider for a moment this struetiu'e with reference to 

 its comparative morphology. 



When the specimens of SquamuUna scopula are dried, they 

 are very prone to fall off from their attachment to the fueus ; 

 and then they invariably leave the bottom or disk of the pe- 

 destal adherent to the former — which at once enables ns to see 

 the disk on the fueus (figs. 6 & 7), and the vault of the convex 

 pedestal still connected with the broken-off column (Hg. 8 a). 



If we iirst look at the disk adhering to the fueus (figs. 6 & 7), 

 we shall observe that it is more or less white, being composed 

 of the same material as the test, and presenting a more or less 

 uneven ring, from which several processes of unequal length 

 radiate inwards. Five or six, but generally five, of these, as 

 before stated, are much more developed than the rest ; con- 

 stricted towards the circumference and inflated towards the 

 centre of the disk, which they do not reach, but leave, as also 

 before stated, a central area, which forms, with the interspaces 

 between the radii, a single common chamber, continuous, 

 through the aperture of the summit of the jjedestal (fig. 5rt), 

 with the general cavity of the column. The interspaces of the 

 disk are more chitinous perhaps than arenaceous ; that is to 

 say, the test is not near so thick here as in other parts. 



Turning to the coiTcsponding portion of the pedestal still at- 

 tached to the column (figs.8 <fc 9), we observe that these radiated 

 portions of the disk belong to as many pseudo-septal divisions 

 which, extending upwards, at last lose themselves U])on the 

 dome of the pedestal, near the margin of its aperture, and that, 

 in the dried state, a contracted mass of dark brown sarcode («) 

 at this point presents, in its still lobed form (fig. 9«), the indica- 

 tion of its once (when living) having occupied the interspaces 

 between the septal divisions of the pedestal. 



Now this radiated disk undoubtedly has very much the 

 appearance of the radiated septa of a coral-polype ; but it has 

 a still nearer affinity to the septal divisions of a nautiloid 

 foraminiferous test ; and when we compare the whole structure 

 of the pedestal with the latter, we cannot help seeing that the 

 septal divisions are homologous with the septa of a nautiloid 

 foraminiferous test, and that the central area corresponds 

 with the initial or primary cell of a nautiloid individual, 

 which, on being prolonged upwards, in SquamuUna scojyula, 

 developes a column at the expense of the spire. 



Following u]) this view, I by chance found a pedestal a/o«e, 

 which 1 have mounted in balsam and drawn as one of the 



