284 
Speaking generally, I regard ccenenchyme as an elaboration 
or extension of mural and murocostate structures, formed above 
or within the epitheca. 
I have above referred exclusively to the kind of wall which 
has been termed a ‘‘eutheca” (Fig. 8) or ‘‘true theca.” Dr. 
Ortmann has defined it as a wall having distinct centres of 
calcification independent of these in the septa. In the case of 
ep. = 
th. 
—Eutheca. Transverse section showing the structural relations of 
= septa, c.= costa, ##.=theca, and ef.= epitheca, ina typical Turbin- 
olid. The section is cut some little distance below the calycinal edge. 
the primitive one-sided wall, I would remark that the layers are 
often so smooth, that no particularly marked ring of ‘‘ centres ” 
is seen next the epitheca. 
The ‘‘ pseudotheca”’ (Fig. 9) is defined as a ‘“‘false wall” 
formed by lateral thickening of the septa, with or without the 
participation of basal structures. I find that ‘‘ pseudothecal ” 
thickening is a very general characteristic in the families with 
Fic. 
9.—Psenudotheca. 
Transverse section showing the structural relations 
between s.= 
eptum, c.= costa, ps.t#.= pseudotheva. and ef. =epitheca. 
All grades occur between a position of the pseudctheca very near the 
centre and very remote from it, until it may be almost coalescent with 
the epitheca ; the costa is respectively longer or shorter. 
Pollaplophractic septa. Two walls, z.e. both pseudotheca and 
eutheca, were present temporarily or permanently in many fossil 
colonial genera belonging to Cyathophyllidee, Stylinidze, Amphia- 
streeidee, but, asa rule, the permanent presence of a pseudotheca 
1s correlated with retrogression or absence of the primitive wall- 
lining of the epitheca, and even the epitheca itself, around 
individual calyces. 
Evolution in the general Architecture of the Calyx. 
_ The internal construction’ of the calyx has altered very con- 
siderably during the history of the Madreporaria. Originally, 
the Madreporarian calyx was shallow, with low septa ribbing 
the walls and base, and from one to four grooves (fossulze) in 
the wall and base. Now, it has become typically deep-cupped, 
the septa are relatively higher and more ornate, centrally a 
columellar “style” rises upwards. or the septal ends meet 
irregularly in a columellar mesh-work, and instead of one to four 
special grooves, it is as if the whole base of the cup were 
grooved and deepened. These changes I take to be correlated, 
and to have been initiated by an increase in the number of 
mesenteries bearing reproductive organs, and increase in the 
demand for space in which to accommodate and protect these 
organs tn the calyx. It is generally presumed that the primitive 
fossula were pits for the accommodation of a very few 
mesenteries specialised for reproduction. | Whereas now 
all, or nearly all of the mesenteries in living corals can exert 
this function. The multiplication of reproductive organs in any 
species is, we may safely argue, an advantage to it in propa- 
gating its kind; certainly it is a change which has proved 
successful in all Madreporarian families adopting it. The 
Cyathophyllids were the most precocious of the Paleozoic corals 
in modifying their calyx; and I attribute to this fact the 
arvellous rapidity with which their descendants, the families 
NO. 1421, VOL. 55] 
NATURE 
= 
[JANUARY 21, 1897 
of Astrzeidze and Fungidee, spread over early Mesozoic seas. To 
this day these families are probably the richest in genera and 
species. 
The change in the architecture of the calyx was effected by 
a gradual modification of existing skeletal structures. The 
“tabula” degenerated or was changed to ‘‘ columella” ; it was 
only retained in its primitive form in the calyces of polyps which 
have never specially multiplied the number of their mesenteries, 
but have held their place owing to some other advantageous 
resource, ¢.g. ccenosarc. These are comparatively few. 
The wall-lining of the epitheca was modified as I have 
indicated above. The septa were modified, giving rise to 
pseudothecz inside the calyx, a valuable means for the support 
of mesenteries. In living families, the complicate Pollaplo- 
phractic type of septum goes hand in hand with much pleating 
and greater muscular vigour of the mesenteries. There can be 
little doubt that higher musculature and sensibility of mesenteries 
aids reproduction, hence these correlated features in septa and 
mesenteries were probably adaptations to this end. The synap- 
ticular base is another modification closely associated with the 
mesenteries, occurring as an occasional correlate in types with 
Pollaplophractic septa and a much-pleated aboral polypal 
surface. 
In short, by comparison with well-known facts in the anatomy 
of living Madreporaria, it becomes clear that all the important 
changes which have taken place in the history of the group, are 
secondary features correlative with change in the mesenteries. 
There is also good evidence that the change in the mesenteries 
has assisted the polyp’s powers of propagation. We need look 
no further for an explanation of the ‘‘ hastening” in the stages of 
cyclical development of mesenteries orsepta. The history of the 
embryo summarises that of the race ; tetrameral symmetry is now 
for the most part an evanescent phase in embryonic develop- 
ment. On this point, any evidence I have gathered from 
Mesozoic corals only corroborates the published views of Prof. 
Quelch and Dr. Ortmann against a subdivision of Madreporaria 
into Tetracoralla (Rugosa) and Hexacoralla, and helps to still 
more emphatically knit continuity into the thread of Madrepor- 
arian descent from Paleozoic to recent time. Even now the 
change to radial symmetry of the polyp is often incomplete, and 
will be while there still are ‘‘ directive ’’ mesenteries. 
In conclusion, I claim in this work to have shown that the 
great impulse of evolution—viz. the successful continuation of 
the race—is the agent to whose steady working the main changes 
in Madreporaria may be traced. I claim to have vindicated 
this position by demonstrating the same structural unit in the 
simplest and the most complicate skeletal structures known in 
Madreporaria through all ages, by finding in all skeletal parts 
one and the same fibrous equivalent of the living, lime-forming, 
unit cell, and by tracing a correlated series of modifications 
which primitive forms have undergone in response to the need 
of safeguarding the race. Maria M, OGILVIE. 
THE POSITION AND WORK OF THE 
CENTRAL TECHNICAL COLLEGE. 
TE 
E Report of the Special Committee appointed by the 
Governors of the City and Guilds of London Institute, at 
the instance of the Court of Assistants of the Mercers’ Com- 
pany, to inquire into the expenditure of the Central Technical 
College as compared with results, has just been published. 
The Committee comprised not merely representative members 
of the City Companies, but present and past Presidents of the. 
Royal Society, the Institution of Civil Engineers, the Chemical 
Society, and other societies interested in the advancement of 
knowledge, so that its opinion may be regarded as that of the 
scientific public. Sir John Donnelly was elected chairman of 
the Committee. 
The volume runs into eighty pages, and deals with (1) building 
and equipment, (2) current expenses, (3) cost of the College per 
student and comparison with other colleges, (4) methods of ad- 
ministration and control over expenditure. We are glad to 
give it prominence, first, because the Central Technical College 
is not supported as acommercial concern to make money, but to 
provide, at small cost, a sound education in the applications of 
the principles of science to industry ; and secondly, because the 
members of the teaching-staff are earnest and enthusiastic in 
their efforts to carry ont the scheme formulated some years ago, 
when the estimates of the cost of the College were drawn up by 
Huxley and others. 
