DR. G. J. HINDE ON RECEPTACULITID 2”. 799 
p. 136), states that it is a sponge, and that he proposed the term 
Spherospongia for the Devonian species. At the same time he 
mentions a Caradoc fossil (without adding any further description) 
as of the same genus, in which, as will be shown, he was mistaken. 
Whether, however, we regard Pengelly or Salter as the author of 
the term, there is no doubt that it was first applied to the Devonian 
species Spheronites tessellatus, Phill., and this form will thus remain 
as the type, and the genus will not be invalidated by the circum- 
stance that Salter ranged under it, several years later, other forms 
which have no relationship whatever with the type species. Salter 
further states, in the same memoir, that Jschadites is a regularly 
formed sponge, with vertical and transverse bundles of fibres, and 
that he now regarded fteceptaculites also as a very regular cup- 
shaped sponge, with a skeleton arranged precisely after the pattern 
of the soft parts in Orbitolites. 
According to Miller’s ‘ Catalogue of American Paleozoic Fossils ’ 
Prof. Hall has described in the ‘ Report of the Superintendent of the 
Geological Survey of Wisconsin, 1861,’ five species of Receptaculites 
from strata of Trenton and Niagara age. I have in vain sought for 
a copy of the pamphlet containing this Report in the libraries of the 
scientific societies of London, and cannot therefore express an 
opinion as to the character of these species. 
Mr. E. Billings, in the ‘ Paleozoic Fossils of Canada’ (1865), 
vol. i. p. 378, gave an elaborate description of the structure of 
Receptaculites, based principally on the characters of FR. occidentals, 
Salt. He described the genus as consisting of discoid, cylindrical, 
ovate, or globular-shaped bodies, hollow within, and usually, if not 
always, with an aperture in the upper side. He supposed that even 
the large flattened examples of &. occidentalis were but the basal 
portions of conical hollow individuals, of which the upper portions 
had fallen to pieces after the death of the animal. The body-wall, 
according to Billings, consisted of three parts, an external integu- 
ment, the ectorhin, and an internal, the endorhin, composed of 
rhomboidal plates, between which are cylindrical hollow tubes or 
spicules, which extend between plates of the outer and inner sur- 
face. The outer extremity of each spicule carries four small slender 
stolons extending to the four corners of the plate which covers 
them, and Billings states that they seem to form a connexion with 
the stolons of adjacent spicules. The plates of the endorhin are 
said to possess four small canals which radiate from the centre of 
each plate (where they communicate with the vertical spicule) to 
each of its sides; and further a circular orifice is present at the - 
angles of the plates. JBillings’s description is supplemented by dia- 
grammatic representations of a vertical section of a subconical 
species and of the structure of the body-wall. It ought not to be 
forgotien that these figures are merely diagrammatical, and I do not 
think any conical form has ever been discovered with an interior 
plate like that figured by Billings, though it fairly represents the 
structure of the open cup-shaped examples of Receptaculites. Billings 
recognized the affinity between Meceptaculites and the genera Tetra- 
