Genus £thmocyathus, Bedford. 
Ethmocyathus lineatus, the genotype and only species 
so far found, differs considerably from such genera as 
Cyclocyathus, as it has three or four minute horizontal 
rings running across each pore of the inner wall. 
Family Tercyathidae Vologdin. 
The two genera of this family are described si 
Vologdin as follows: 
^ 
Genus Tercyathus Vologdin. 
The external wall is costate, reticulate; the internal 
wall has a spongy structure and is thickened to the 
size of the intervallum. 
Genus Clathricyathus Vologdin. 
The external wall is porous and of a reticulate struc- 
` ture, while the internal wall is highly complicated, after 
the type of genus Ethmophyllum. 
In Fig. 189 we give a transverse section of Tercyathus 
altaicus roughly sketched after a figure of Vologdin's 
These genera appear, to be related to the mare 
thidae. 
Family o iis Taylor. 
Clear small spitzes of Coscinocyathus are difficult to 
find in the Ajax Mine material, as secondary silicifica- 
tion often masks the outer wall pores and the internal 
detail. One of the best fragmenis of a small spitz we 
have found is shown in Plate XLVI, Fig. 190. The 
transverse section, A, as first exposed at a diameter of 
13 mm. showed a tabula, and this was apparently the. 
first to be formed, as, when the wall was ground away 
lo show the internal structure in. longitudinal section, 
b, no lower tabulae were indicated. The lowest part 
of the fragment, at 2/3 mim. diameter, seems to have 
a typical “Alphacyathus spitz” structure, with septal 
rods beginning to give place to septa. Outer wall 
pores are obscured. Fig. 191 shows a spitz from 2-2/5 
mm. diameter above to 14 mm. below; outer wall pores 
ure visible at the upper left hand, obscured below. Fig. 
192 shows longitudinal and transverse sections of a 
spitz from 34 mm. to 13 mm. diameter. In both the 
latter spitzes the small relative size of the central cavity 
is noticeable. Fig. 193, Plate XLVII, shows successive 
transverse sections of a spitz from 31 mm. to 14 mm. 
diameter; the lower part is obscured by Aio 
the upper part shows four rows of outer wall pores to 
the intersept. Fig. 194 is of a 34 mm. spitz coated 
externally and with endothecal tissue in the central 
cavity. A spitz of 5 mm. to 3 mm. diameter is shown 
in Plate XLVII, Fig. 195; this has a slightly fluted 
outer wall, with two rows of pores to each intersept. 
` Part of an unusual cluster of Coscinocyathus spitzes, 
surrounded by exothecal tissue, is shown in Plate 
XLVII, Fig. 196. We regard the latter as an incrust- 
ing or parasitic organism; the state of preservation. 
however. QE to. the presence of much extraneous 
76 
silicification in the specimen, prevents correlation with 
Exocyatnus or other investing forms. 
Genus Coscinoptycha, Taylor. 
An interesting spitz is figured in Plate XLVII, Fig. 
197. It is unusual in having the outer wall pores much 
larger than the inner, and is of the type described by 
Taylor as Coscinoptycha convoluta and the closely re- 
lated species with narrower intervallum described by 
us as Coscinoptycha unilinearis. 
coarse pored wall as the inner one; he had only ex- 
panded fragments from the upper part for study, but 
our specimens show clearly that the coarse pored wall 
is the outer one. In view of the unusual shape and 
details it is desirable to retain Taylor's generic name 
with this form as genotype. But his Coscinoptycha 
bilateralis is, in details, of the usual Coscinocyathus 
type, allied, as Taylor suggested, to Coscinocyathus 
australis, and should be removed to that genus. 
Family Putapacyathidae, Bedford. 
The genotype Puiapacythus regularis is described in 
our third memoir, p. 24. It is a very remarkable and 
well characterised form, having specialised outer and 
inner walls and numerous clearly defined tabulae, but 
with septa entirely wanting. We have now found a 
spitz which appears to belong to this species. It is 
shown in Plate XLVIII. Fig. 198. The stone was 
broken across when found, so that the spitz was in two 
pieces A and B; we afterwards ground away part of 
the outer wall of A to expose the inner 
tabulae, as shown in C. The spitz, which is from 
14 to 14 mm. diameter, does not show outer wall pores; 
probably these are obscured by silicification. The inner 
wall is vertically ribbed and has a line of pores between 
each pair of ridges. Tabulae are seen but no septa. 
The lower part ات‎ B is missing to such an extent 
that only a slip of outer wall remains with the edge of 
four tabulae; no doubt the inner wall was originally 
present at this level. It is to be noted that the evidence 
is insufficient yet to identify this spitz as being com- 
pletely of “Alphacyathus type." We refer 
point again in connection with the next family. 
APPENDIX TO ORDER AIACICY ATHINA. 
New Family Sigmocoscinidae. 
Genus Sigmocoscinus, Bedford. 
The genotype Sigmocoscinus sigma was described by 
us in our third paper, p. 29, Plate XXII, Fig. 93. The 
genus was defined as cups with regular straight septa. | 
tabulae of the normal Coscinocyathus type and con- 
tinuous anular sigmoid plates inside, the inner wall. 
It may be gika that, though these plates appear 
continuous in an inner view of ‘the inner wall surface 
(Fig. 98E). the ends of the septa project inwards to 
some extent to join the sigmoid plates, so that in trans- ——— 
Taylor considered the . 
wall and. 
to قلطا‎ 
