360 
MR. W. K. PARKER AND PROFESSOR T. R. JONES ON SOME 
(figs. 39, 42, 43). Indeed in specimens having five chambers we have distinguished a 
tube in each chamber. In large individuals the apertural plicae grow quite as far into 
the chamber as they project outwards. Thus the Entosolenian character of aperture is 
generally present ; and though the mouth does not pout so much as in many of the 
Nodosarite and Lagence, yet the last chamber not unfrequently sends out a dendritic 
growth of exserted apertural tubes — a character noticed by us in a large Lagena also 
common in the Tertiary beds of Grignon (see p. 354). Nor is this feature unrepresented 
among the Nodosarice , as shown by the dichotomous Dentalina aculeata , D’Orb., of the 
Chalk and Gault. 
The shell of Polymorphina has usually a glassy smoothness ; it rarely shows any ten- 
dency to striation ; when this occurs, it is longitudinal, but feeble, and then arises from, 
apparently, the fusion of granules arranged in rows ; whereas in the three most cognate 
species ( Nodosarina , Lagena , and Uvigerina ) striation and strong costation of the cham- 
ber-walls are extremely common. It has, however, at times another mode of ornament, 
such as is not unfrequently met with in the Nodosarine and Uvigerine groups, and 
especially in the Globigerince of the deep seas in low latitudes, and in Calcarina , — 
namely, prickles or long needles of shell-substance bristling over the surface. Another 
surface-ornament is common in large well-grown Polymorphince , especially those of the 
Crag of Suffolk (Mr. S. V. Wood’s Collection), which have a rich granulation of clear, 
polished, calcareous beads and lobules scattered over the whole surface, but most 
strongly on the older chamber-walls. A like granular ornament is common in the very 
large distomatous Lagenas from the Australian shores (as already mentioned). The best 
example of the development of this particular ornament is seen in the great explanate 
Cristellarice of the Tertiary beds of Malaga, Sienna, and Turin. 
In the form before us (figs. 45 & 46) we have a subglobular condition of P. lactea , 
Walker and Jacob. Fig. 46 is the young, showing, by transparency, the long Entoso- 
lenian neck, as well as the radiated aperture. It has but two chambers, the second of 
which is relatively small; in after-growth the chambers increase in size rapidly but 
irregularly, and overlap each other in proportion to the gibbosity of the shell. We 
possess complanate or leaf-shaped forms, such as are figured by D’Orbignt in his 
For. Foss. Vienne, pi. 13. figs. 25-30, in which there is scarcely the least overlapping 
of the chambers. 
The two chambers of fig. 46 are the “primordial” and “ circumambient” chambers of 
other polythalamous Foraminifera. We have seen a similar double-celled condition of 
shell belonging to young forms within the chambers of the mother-shell, in Truncatulina 
lolatula (from south coast of England), Peneroplis pertusus (from India), and in large 
Orbitolites complanatus (from Fiji). In the last (some specimens of which were full an 
inch in diameter) we found the mother-chambers, towards the periphery of the shell, 
crowded with young ones*. 
* These specimens, both old and young, may be seen in the Hunterian Museum, Royal College of Surgeons 
(See Catal. Mus. Plants and Invertebr. 1860, p. 96, No. A 54) ; and have been described by Dr. Carpenter, 
Introd. Foram., Ray Soc. p. 38. 
