DR. G. J. HINDE ON RECEPTACULITIDA, 821 
Genus Recepracurites, Defrance, 1827. 
Rteceptaculites, Defrance, Dictionnaire des Sciences Naturelles, t. 
45, Atlas, pl. 68. 
The typical examples of this species to which the author gave the 
name of &. Neptwni were from Devonian strata at Chimay in 
Belgium, and consisted, judging from the figures, of two individuals, 
one cup-shaped and the other a flat disk-shaped specimen. The cha- 
racters of these specimens were evidently very imperfectly preserved, 
and the author merely refers to an outer surface of rough markings 
and protuberances arranged in regular curved lines, and an upper 
surface exhibiting round shallow holes. Succeeding writers, with 
the exception of Salter and Billings, have based their descriptions 
of the genus upon specimens of the same species from Belgium and 
Silesia, whilst these latter authors have referred more particularly 
to species from a lower geological horizon in Canada and Australia, 
which, in some structural details, differ from the Devonian forms 
described by Dames, Gumbel, and others; but it is doubtful if these 
differences really exist or are merely owing to the imperfect 
preservation of the specimens. The following description is from 
the study of specimens from Devonian strata in Belgium, Silesia, and 
Canada, and from Silurian strata in the United States, Canada, the 
Arctic regions, and the Baltic. 
In outer form the examples of this genus are open cup-shaped or 
flattened expansions with a circular outline and sometimes with 
slightly incurved margins. Numerous gradations occur between 
cup- and platter-shaped examples of the same species. In some 
specimens there appears to be no tendency to an incurvature at the 
margins, even in very large forms, such as those of LR. occidentalis ; 
while in others there is a short upward curvature, so that when 
complete they must have resembled a wide, shallow, dish. The 
nucleus, or starting-point of growth, is usually a small obtusely 
conical projection, which in no wise served as a point of attach- 
ment, and the organism is invariably free. Whether the margins 
of the cup were open or covered in any way is uncertain, as in no 
case is the structure of the upper edge clearly shown. ‘There seems 
no evidence in fayour of the supposition of Mr. Billings that the 
complete specimens of this genus possessed dome-shaped or conical 
summits similar to those of Ischadites, for though platter- and cup- 
shaped examples are abundant in certain strata, and apparently 
perfect as regards their outer form, yet in no single instance has an 
upper portion been discovered in connection with them ; and if we 
take into consideration the numerous instances in which the smaller 
and more delicate forms of Jschadvtes still retain their complete form 
and conical summits, the conclusion appears justifiable, as Gimbel 
has already remarked, that the specimens of Heceptaculites were 
originally of the form in which they are now found as fossils. No 
specimen has yet been found to correspond with the diagrammatic 
representation which Mr. Billings * has given of a supposed complete 
example of the genus. 
* Pal. Foss. vol. i. p. 378, f. 353. 
Q.J.G.8. No. 160. 31 
