324 Mr. F. Chapman on 
in material collected by Mr. John Young, of the Hunterian 
Museum, Glasgow. It also occurs in the Silurian clay of the 
island of Gothland. The arenaceous material constituting the 
test of the Silurian specimens, unlike that of Rhetic examples, 
is cemented by calcareous matter. 
The tests of S. amplexa from Wedmore have been largely 
constructed of the crystalline aggregates to which reference 
has previously been made, and of which only moulds now 
remain to testify to their former existence. ‘These crystal- 
line bodies were also used in the construction of the tests of 
the other large subarenaceous species from the Rhetic 
washings, belonging to the genera Nodosinella and Stacheta ; 
but they occur in S. amplexa in particular abundance. 
S. ampleaa was found in the Rheetic series at Wedmore, 
in bed no. 3, frequent ; no. 5, common. 
21. Stacheia dispansa, sp.n. (PI. XII. fig. 8.) 
Test free, compressed, and generally irregular in outline ; 
some more or less perfect examples, however, have a leaf-like 
form with deeply incised margins. Interior traversed by 
irregular sinuous cavities, which are at intervals transversely 
divided. The positions of the apertures in this compressed 
form are—(1) around the margin, appearing as an interrupted 
slit communicating directly with the interior, and constituting 
a plane of weakness through the median plane of the test; 
(2) disposed over the surfaces of the test as a series of irre- 
gularly circular orifices, which are often siphonate, that is, 
borne on the end of a short tube projecting at right angles 
from the general surface, the latter being in some cases 
modified by lateral compression, thus giving the orifice an 
elliptical or slit-like form. Wall of test very thick and with 
a finely labyrinthic structure. Length of one of the more 
perfect specimens } inch (12°5 millim.), breadth 3 inch 
(6°25 millim.), thickness s inch (1 millim.). 
The fragmentary remains of this species constitute a large 
proportion of the washed material from one stratum of the 
Rheetic series at Wedmore. SS. dispansa does not seem to 
have ever been attached to any foreign bodies like some of 
its congeners, but to have lived on the surface of the deposit 
forming at that time. One of the specimens found has a 
very definite outline, taking a form such as one would imagine 
to arise from the extrusion of the sarcode in an amcebiform or 
lobulate manner. The majority of the specimens of S. dis- 
pansa have, however, no very distinct shape, and are always 
more or less fragmentary, since the mere separation of the 
