No. 1614. NEW AND OLD CARBOCSIFEROUS FOSSILS—GIRTY. 285 
semblance to eterocalia and its difference from Cwlocladia it seems 
probable that J/wandrostia also is one of the Calcispongie. 
Maandrostia more nearly resembles a sponge from the Guadalupe 
Mountains for which I have proposed the name Cystothalamia than 
any other genus known to me. Some of the differences which can be 
noted are these: Cystothalamia seems to be without a persistent 
central cloaca. The outer wall appears to be porous instead of solid. 
The ostia are prolonged as spout-like projections. The chambers 
produce swellings upon the exterior, to which they give a cystose 
appearance. The differences last mentioned may perhaps be regarded 
as only specific, but the first two are clearly generic. The material 
from the Guadalupe Mountains, however, is not well preserved, and 
it is impossible to state with complete certainty that there is no persist- 
ent cloaca, though the porosity of the outer wall is open to but little 
question. It hardly seems permissible, therefore, to regard the pres- 
ent type as generically the same as Cystothalamia. 
Type of the genus.—M ceandrostia hansasensis. . 
MAANDROSTIA KANSASENSIS, new species. 
Plate XV, figs. 1-7. 
The form for which this name is proposed consists of slender, sub- 
eylindrical, occasionally branching bodies, which rarely exceed 
13 mm. in diameter, but are often much smaller. As a rule they are 
nearly straight, but may be considerably contorted. The exterior is 
made irregular by inequalities of growth, and further roughened by 
large numbers of ostia, some of which appear to have slightly elevated 
margins. The ostia are circular, and average about 0.75 mm. in 
diameter. The interior is occupied by a central tubular cloaca, which 
apparently passes uninterruptedly through the complete length of 
the stem. The space between the cloaca and the periphery is filled 
in by vermiform chambers, which communicate with the exterior 
by means of the ostia and also intercommunicating with each other 
and with the cloaca by frequent irregular apertures in the walls. In 
different specimens, and probably in the same specimen at different 
points, this structure while the same in principle varies considerably 
in detail. A tube-lke cloaca is usually a striking feature, but occa- 
sionally it is hardly to be distinguished from the generally irregular 
porous structure. ‘The cloaca varies considerably in size, sometimes 
occupying less than one-third the entire diameter, at others having 
only a thin rim of wall about it. Similarly, in some sections the 
partitions are so developed at the expense of the chambers that the 
stem appears to be well-nigh solid. In others the partitions are thin 
and disconnected, leaving the interior all but open. 
The walls appear structureless, and but for the openings already 
described are imperforate. The outer wall especially is pierced by 
