SILURIAN NONDESCRIPTS. 



697 



es This fossil is most analogous to a very singular body described by Lamarck under the 

 name of Spongia Labellum. The Spongia Labellum cannot remain among the Sponges, 

 properly so called, but ought to form the type of a particular genus. It is composed of rather 

 slender, foliaceous laminas, arranged in an infundibuliform manner, and formed of cylindrical, 

 longitudinal and slender shoots (tigelles), which ramify and anastomose among each other, and 

 are covered by a kind of parenchymatous membrane which occupies equally the meshes left by 

 this tissue. 



" In short, I believe that this fossil of the Ludlow Rocks ought to form the type of a parti- 

 cular genus in the great family of Sponges, and may be characterized provisionally as follows, 

 until the structure of the body is studied. 



" A foliaceous, orbicular body, attached by its centre, and presenting a great number of sali- 

 ent, divergent ridges, which divide successively into several centrifugal branches, and appear 

 to be covered by a membrane having circular and concentric folds." — Translation and Ex- 

 tract of a letter from Dr. Milne Edwards. 



Loc. Bircher Common, near Aymestry, where it was found in the Upper Ludlow Rock by 



the Rev. T. T. Lewis. 

 Cophinus dubius, PL 26. f. 12. 



This is a nondescript fossil concerning the origin of which no naturalist has yet given a de- 

 cisive opinion. It has been referred with doubts to the family of soft Zoophytes, Crinoidea, 

 and to Mollusca ; so wide from each other are the guesses as to its place in the natural order 1 . 

 All we can say with certainty is, that it has the shape of an inverted four-sided pyramid, with 

 a column-like rounding off at each corner, and 4 inter columniations or sides, transversely 

 situated, producing the appearance of basket-work', whence, whatever it may prove to be, 

 the fossil is provisionally named, at the suggestion of Mr. Konig, Cophinus (wicker basket). 

 This curious body has been adverted to in the text (p. 181.) as occurring in positions more or 

 less vertical in the uppermost strata of the Ludlow Rock, from which I infer that the animal 

 was attached by the end of the inverted cone, while the finely levigated muddy sediment accu- 

 mulated around the columns or stems. 



I am indebted to Mr. W. Evans not only for collecting the best specimens of Cophinus with 

 which I am acquainted, but also for directing my attention to the vertical position of the fossil 

 in the Upper Ludlow Rock. As the drawing in the wood-cut was taken from an imperfect 

 and broken specimen, I have in this plate given a more perfect representation of the fossil. 

 Ischadites Konigii, PI. 26. f. 11. 



These curious fossils are so grouped together, that I always compared them with " packed or 

 pressed figs and Mr. Konig, to whom I referred them, thus speaks of them. " I am of opinion 

 that they may be considered to belong to the family of Ascidicz. Like the Leucophthalmus of the 

 Icones Sectiles (Cent. 1. f. 1.), they seem to form a group of globular, coriaceous, and, it may 

 be added, pedicled bodies, for in one of them the cicatrix for the insertion of the pedicle di- 

 stinctly appears. As, however, no traces of branchial and intestinal apertures are apparent on 

 the surface exposed to view, it would be rash to constitute this fossil a genus, or to assign it a 

 place in any of the known genera of the order of the naked Mollusca, to which Leucophthal- 

 mus unquestionably belongs." 



1 When the Chapters on the Ludlow Rock were printing, I was led to consider the Cophinus a soft Zoophyte, 

 allied to " Sea Pens." See p. 206. 



