SHELLS OF THE WENLOCK LIMESTONE. 



627 



umbo in the centre and a deep depression at each of the most remote angles, bearing much re- 

 semblance to two siphuncles; its surface is marked with short striae in the direction of its longest 

 diameter, giving it an aspect totally different from that of the septum in Orthoceras. It is one 

 of the few animals of the Silurian period, whose existence would at first sight seem to have 

 been prolonged beyond the aera of the Old Red Sandstone, for forms, approaching very near to 

 our specimens, are found in the ironstone nodules of the carboniferous series. In the Min. Con. 

 no distinction is drawn between the specimens from the transition limestone and those from the 

 carboniferous ironstone. By close comparison, however, it would appear that different species 

 may be established ; for the obliquely transverse furrows in the former are crossed by little 

 grooves very regularly arranged over the shell, while in the ironstone specimens the correspond- 

 ing furrows are either smooth or irregularly grooved ; the ridges in both appear when perfect 

 to be crenated, but most distinctly so in the specimens from Coal Brook Dale, from whence 

 Mr. Prestwich has a large collection. If this structure of the surface be sufficient to indicate 

 two distinct species, one must retain the original name, and the other may have that given by 

 Defrance. 



By some accident, Hisinger has given to this genus, Lamarck's generic character of Conilites, 

 which is probably only the alveolus of a Belemnite?. He may possibly have taken the Conularia 

 teres, M. C, for the type of the genus, the square form not having been mentioned in the generic 

 character ; but that species it is said, "probably belongs to another genus." Defrance (see De 

 Blainville as above) has referred to both species as different portions of the same. His figures 

 are copied from Mineral Conchology. 

 Loc. Wenlock, Dudley, fyc. 

 Bellerophon apertus. (M. C. t. 469.) (See PI. 13. f. 21.) Also Wenlock Shale. 

 Loc. Ledbury. 



Bellerophon dilatatus, f. 23 and 24. Discoid, smooth ; sides largely umbilicated ; margin broad, 

 slightly convex, with a central ridge ; whorls few ; aperture suddenly dilated to a much greater 

 diameter than the spire, and inclosing it, orbicular. Diameter of the spire 1 inch 8 lines, thick- 

 ness 1 inch, longest diameter of the aperture 3 inches, rather longer than wide. 



The last whorl, before it expands to form the large aperture, is twice as wide as long. The 

 edge of the aperture embraces two thirds of the discoid spire ; the front of it has no fissure, al- 

 though there is a ridge upon the whorl which indicates the existence of such a fissure at an 

 earlier period of growth. 



Two of our specimens show furrows inside the mouth ; the one from the Lower Ludlow 

 Rock is nearly smooth, but has slight indications of them : may not the former be impressions 

 of the outer surface ? 

 Loc. Burrington near Ludlow. 



Cornulites serpularius, Schlot. PI. 26. f. 5. (Schloth. Petr. t. xxix. f. 7-) We can scarcely attempt a 

 description of this anomalous fossil, of which at present but one species is known. So unlike 

 is it to anything we have seen, that we are unable to assign it a place in the system of animals, 

 or draw a comparison between it and any other creature. Its general form is a much elongated, 

 hollow, more or less crooked cone, open at the base ; in its early state it is parasitical, being 

 attached by its side and often in pairs. The external crust is longitudinally striated, and 

 marked with slightly raised rings, which indicate its passage over the margins of the series of 

 truncated cones of which the fabric is constructed. These short cones are placed within each 

 other, their widest edges being directed towards the apex of the general envelope, the smallest 



