Archeocyathus, and other Genera. 373 
On ARCH2ZOCYATHUS, BILLINGS, AND ON OTHER 
GENERA ALLIED THERETO, OR ASSOCIATED THERE- 
WITH FROM THE CAMBRIAN STRATA OF NORTH 
AMERICA, SPAIN, SARDINIA AND SCOTLAND. 
By Dr G. J. Hrnpp, F.GS. 
( Abstract.) 
A revision of the type specimens of the three species in- 
cluded by Mr. Billings in the genus Archeocyathus shows that 
each of the species represents a distinct genus. <Archwo- 
cyathus profundus, having been selected by Mr. Billings in 
1865 as the typical species, was retained as such, and the 
characters of the genus, as shown in this species were 
defined ; Arch. atlanticus, Bill., was made the type of a new 
genus, Spirocyathus ; and the third species, Arch. minganensis, 
which proves to be a siliceous sponge, was included in a new 
genus, Archwoscyphia. 
Including the genera allied to Archwocyathus, described by 
Meek and Bornemann, the following constitute the family 
ARCH ZOCYATHIN”, proposed by this last-named author ; 
Archeocyathus, Bill. ; Hihmophyllum, Meek ; Coscinocyathus, 
Born.; Anthomorpha, Born.; Protopharetra, Born.; and 
Spirocyathus, gn. 
The genera of this family are characterized for the most 
part by turbinate or subcylindrical forms with stout walls 
enclosing an interior tubular or cup-shaded cavity. Their 
skeletons are carbonate of lime in a minutely granular con- 
dition. The walls in the first four of the above-named 
genera consist of an outer and inner lamina connected by 
vertical and radial septa ; dissepiments are generally pre- 
sent between the septa; save in the genus Anthomorpha, the 
outer lamina of the wall is regularly and minutely perforate, 
and the inner lamina and septa are likewise cribriform ; 
Lthmophylum is particularly distinguished by oblique canals 
connecting the interspaces of the wall with the central 
cavity, CVoscinocyathus by transverse, perforate tabule, and 
Anthomorpha by the apparently imperforate character of the 
surface-laminw and septa. Protopharetra and Spirocyathus 
