253 
Bellerophon IBoodlOardii, J. Pliillips, 1836, Geol. Yorkshire, II, p. 231, pi. 17, fig. 1, 2, 
3 (nou idem. Pal. Foss., p. 107, pi. 40, fig. 201). 
,, ,, A. d’Orbigny, Mou. Genre Belleroplion, pi. 6, fig. 17-19. 
Borcellia ,, L. G. de Koninck, 1844, Descr. Anim. Foss. Terr. Garb. Belg., 
p. 360, pi. 28, fig. 2. 
„ ,, J. Morris, 1854, Cat. Brit. Foss,, p. 289. 
This shell has much the same appearance as the Ammonites, and was 
at first confounded with them. It is discoidal and concave at both sides. 
There are seven or eight whorls, which do not clasp each other hut are 
angular at both sides ; their external transverse section is snh-pentagonal. 
The surface is ornamented with small granulations arranged in a longitudinal 
series parallel to the dorsal canal with which the last whorl of the spire is 
furnished ; these granulations appear to have been produced by the inter- 
section of very fine, and at the same time deep, striae, some of which are 
longitudinal to the spiral whorls on which they originate, and the others, 
rather more pronounced, cross the first vertically, recurving a little back- 
wards, so as to form lines parallel with the aperture of the shell. On account 
of the relatively great thickness of the shell the aperture is rounded or 
slightly transverse. Although the several turns of the spire seem regularly 
wliorled on the same plan, and although both sides of the shell are very con- 
cave, yet it is easily seen that one of these sides is a little larger than the 
other, and that the first whorls of the spire project slightly ; this is positive 
proof of the relationship existing between Porcellia and Bleurotomaria, in 
which the external edge of the aperture has a slit which by its gradual 
obliteration gives rise to the formation of a band as long as the spiral whorls. 
Dimensions. — This species can acquire a diameter of about three centi- 
metres. The diameter of the largest Australian specimen is only eleven 
millimetres. 
Delations and Differences. — This differs from P. Duzo, Leveille, by 
the angularity of its whorls, and by the complete absence of the large 
tubercles independent of the granulations which ornament its surface. 
Horizon and Localities.-— Hhis, species is found inthe ViseandWanlsort 
Limestone, Belgium, at Bolland and Kulkeagh, Yorkshire, and in the lime- 
stone at Winster and Brassington, Derbyshire. In New South Wales it is 
found at Burragood. I greatly doubt if the Devonian species described under 
this name by Phillips belongs to this species. 
