16 
DE. CAEPENTEE’S EESEAECHES on the EOEAiynNIEEEA. 
ie..ularly arranged punctations, we find a vast number of very minute papilte, scattered 
withou/order OTer the entire surface of the chambers (fig. 6); these, again, inay be 
absent from some parts of a sheU, over other portions of which they are abundantly 
distributed. There is commonly a large semitransparent tubercle at the umbilicus, and 
" tubercles are often seen along the septal bands, especMly of ; 
the umbilical and the septal tubercles are weU seen in Plate IIP fig. ^ 
teristically) in several other figures of the same Plate ; and the sep d tubercles 
shown on a much larger scale in Plate V. fig. 11. Not unfrequently, howeier the 
uinbUicus is depressed, instead of being elevated into a tubercle; and the moniliform 
tubercles along the septal bands are wanting. 0+ 
143 The departures from this typical form, however, are very wide. A glance at 
any considerable aggregation of specimens reveals to us an “dma^ 
and shape; and our attention is speciaUy attracted by a series of which 
represeld in Plate III. fig. 9, which are not merely distingurshed by a s e ^eafly 
above the average-their long diameter reaching nearly -4 
extraordinary flattening of the later convolutions and f 
spire opens out. The approximation between the two lateral walls of the «ei is 
here s^ close, that not only are the septal bands rendered very * 
depression of the outer surface between them, but even the outer 
up as a ridge, from which the walls of the chambers slope down. In fact, an exami 
nation of this form leaves the observer impressed with sui'pnse that any room can 
be left for the animal, the segments of which must be extraordinarily attenuate^ osmg 
in thickness what they gain in area. Now a careful compmson of 
ordinai-y type, not only makes it obvious that the former differs from the latter m 
otLr particular than this attenuation, which (as already pointed out m the cases of 
HeteZtegina and Pmeroplis) is a common featureof the later 
but also that the attenuation takes place in such different degrees in diffmmrt u^— , 
that anv attempt to use it as a ditferential character is completely baffled by the con 
tinuous gradation of forms that is presented, between the one which has been assumed 
as the typical, and such as most widely depart from it in this particular. 
144 The collection of Mr. CuMisa also includes, however, a consMerable proportion 
of comparatively small specimens, ranging from -08 to inch in 
sent a Ly different configuration. In the smallest of these, represented m Plate II . 
fig 1 the’^ spire, instead of being flat or even somewhat hoUowed, is aic ied from i s 
iLr’to its outer margin, so that the breadth of the septal plane is un 
or nearly so ; and the like is seen in the somewhat larger specimens of which fi„. - 
exampJ This variety of conformation, however, being limited to shells whose ear lei 
peld of growth is evinced by their smaller number of convolutions and of chambers 
md being seen, moreover, in the earlier whorls of those which aftenvards pi^seiti th 
m-eatest Lttening, may safely, I think, be regarded as a character of age It u ill be 
recollected that the young of the flattened Peneroplis more resembles Dmdntim m le 
comparttive turgidi/y of fts spire ; but I do not find that 0,erouUna ever continues long 
