abe RESEARCH IN CHINA. 
to 27, are irregular. They are often alternately long and short, but in parts of the 
same corallite may be equal, or in appearance replaced by vesicular tissue. Not 
infrequently one of the smaller (secondary) septa is seen to bend to one side and to 
become confluent with a primary one. ‘The interseptal loculi are rather abundantly 
partitioned by what in cross-sections looks like dissepimental tissue but in reality 
has more the nature of nearly flat horizontal tabule. As previously remarked, the 
septa are often so contorted that they can not be distinguished from the interseptal 
plates with which they intersect. 
The pseudocolumella, which occupies the central area, is fairly distinct from 
the surrounding structures and consists of relatively small concentrically arranged 
cysts, which are nearly vertical in position but with the upper end distinctly inclined 
toward the center. The ends of the septa reach nearly or quite to the pseudo- 
columella, and some of them appear to connect with the plates which compose it. 
As members of the genus Lithostrotion, Lonsdale described and figured a number 
of Lonsdalei# from Uralian Russia, some of which may be related to the form under 
consideration. Lonsdale discriminated his species upon characters which are not 
shown in ordinary conditions of preservation, not, for instance, in the Chinese 
material, and at the same time failed to give precise data regarding features which 
I was able to ascertain. On this account a satisfactory comparison of the present 
form with his species can not be made. It seems to be distinct from the American 
and European types whose descriptions I have seen. No species belonging to the 
genus has as yet been described from China. 
Locality and Horizon.—Pennsylvanian (Wu-shan limestone) ; near Ta-ning-hién, 
East Ssi-ch’uan (stations 1 and 2). 
Michelinia favositoides Girty. 
Plate 29, Figures 1, 2. 
Michelinea favositoides GirtY, 1907, Proc. U. S. Nat. Mus., vol. xxxu1, p. 38. 
Of this species our collection contains a single specimen, which presents the 
following characters: 
The shape appears to have been hemispherical, with a flat base and a width 
greater than the height. ‘The latter dimension is estimated at about 40 mm. and 
the entire width at about 80 mm. ‘The corallites are rather regular in size and 
shape, and usually small, few of them attaining a diameter of 2.5 mm. The septa 
are closely approximate, 11 to 13 occurring in a space of 5mm. ‘They are on the 
whole rather regular, but are distinctly convex and not infrequently confluent. 
Mural pores appear to be present, but, as shown in transverse sections, they are 
rather rare, and their arrangement has not been determined. 
Any statement as to septa depends upon the interpretation of certain appear- 
ances in thin sections. The bounding walls are not thick and show a dense median 
line, which is usually more or less wavy. On either side of the median line is a 
tolerably thick layer, intermediate in transparency between the material filling the 
intertabular spaces and that of the median plate. The inner edge of this supplemen- 
tary wall is rather strongly denticulate, the projections being in some places rather 
regular and in other portions of the same corallite absent or irregular. Whether 
these projections are really denticles or are continuous ridges has not been ascer- 
tained. The tabule show the same degree of transparency as the supplementary 
wall, the projections of which can apparently with justification be interpreted as 
pseudosepta, the dense median line being the plane of cleavage separating the truly 
double-walled corallites. It is hardly possible to count the pseudosepta or to 
ascertain the average number present. 
