210 
DR. carpenter’s RESEARCHES ON THE FORAMINIFERA. 
40. In the specimen represented in fig. 5, the central portion appears to have been 
lost, with about a third of the peripheral ; and the new growth seems to have taken 
place at the same time, from the inner margin aaa oi the fragment, and from its 
outer margin hhh, the two growths becoming continuous with each other along the 
broken edges ab, ah. For although the zones that lie internally to a aa are conform- 
able to those which surround them, yet there is a peculiar character about them 
(more apparent in the specimen than in the drawing) which indicates them to have 
been formed at a later period, and to have been contemporaneous with those which 
surround the zone hhh. Their actual continuity at the angles a a is unfortunately 
interrupted by an injury which the specimen seems subsequently to have received; 
yet its traces are sufficiently perceptible on one side, to justify the belief in its former 
existence. — The specimen of which fig. 4 is a delineation, seems to have been the 
subject of several minor fractures and reparations ; but the course of its zones marks 
out an obvious separation between an earlier- and a later-formed portion, one 
having sprung from the other along the line ah. The incompleteness of the speci- 
men, however, prevents me from coming to any certain conclusion, whether the 
small inner portion is here the older, the large outer portion having grown in the 
first instance from its margin ah, and having gradually extended itself around it; 
or whether the outer portion is the residue of an unusually excentric disk, which, 
having lost its nucleus and the zones immediately surrounding it, has filled up the 
central space with an extension from its innermost zone, which is consequently the 
newest portion of the whole. — It is interesting to find evidence in fossil specimens, 
that the same kind of reparation has taken place. Among the Orbitolites which I 
have examined from the Calcaire grossier of Paris, is a disk of which a large part 
had obviously been lost by fracture, but of which the original symmetry had been in 
great degree restored by a similar outgrowth from the zones formed from the 
uninjured margin, along the fractured edge. 
41. 7’his series of abnormal phenomena, then, not only confirms the conclusion 
that seemed fairly deducible from our previous examination of the normal mode of 
growth, with regard to the independent endowments of the component segments of 
the Orbitolite body, but also affords some additional information of much interest. 
For we see, in the first place, that the growth of the sarcode, and the addition of new 
parts, may take place in the direction of the centre, where a free edge is exposed at 
the inner margin of any zone, as well as in the peripheral direction from the normal 
outer margin. Secondly, the reparative nisus seems always to tend towards the pro- 
duetion of a disk, whose shape shall approach the circular, whatever may be the form 
of the fragment which serves as its foundation ; thus showing that, notwithstanding 
the repetition and independenee of the separate parts of these organisms, each cluster, 
whether large or small, is an integer, having an archetypal symmetry to which it 
tends to conform, — thus strongly reminding us of the laws of crystallization. And 
thirdly, the plan by which this recurrence to the discoidal form is provided for. 
