228 EEV. J. p. BLIKE ON THE 



Kotes and Descri])tions of Portland Fossils. 



Pycnodxjs pagoda, spec. nov. PI. X. fig. 10. 



A small species characterized by the very peculiar arrangement of 

 the teeth on the vomerine bone, which is the only part preseiTed. 

 The general shape of this is long and narrow. It is bounded by a 

 series of close-set oval teeth on each side, with their long axes 

 pointing inwards and backwards. The central line is occupied by 

 six large transversely oblong teeth, which are so far separated as to 

 allow between each pair two obliquely subtriangular teeth of inter- 

 mediate size, having their axes pointing inwards and backwards. 

 All these teeth are quite smooth. 



In the Plinty series at Upway ; found by J. Badcock, Jun., during 

 the visit of the Geologists' Association. 



Ammonites giganteus, Sowerby. 



Portland Ammonites are commonly quoted under this title ; but 

 De Loriol has pointed out that Sowerby's description and figure do 

 not apply to the specimens so named, which have more than twice 

 as many exterior as interior ribs, while in Sowerby's species the ribs 

 only occasionally bifurcate. Such occur only in the building-stones 

 of Portland ; and I have accordingly used De Loriol's name A. holo- 

 niensis for the others. 



Ammonites pseudogigas, spec. nov. 



I confer this name on certain specimens which have on the inner 

 half of the whorl large knobby ribs which bi- and trifurcate. It has 

 the whorl as much inflated as in ^. gigas ; but the ribs are more 

 numerous than the knobs in the latter species and are more truly 

 ribs. 



Ammonites triplicatus, Sowerby. PL X. fig. 7. 



The figure given by Sowerby is of a very small specimen, in which 

 the characters are not well seen. There is, however, a species in 

 the Flinty series to which this name has become attached, but which 

 has never been properly figured, and it is therefore given in PI. X. 

 fig. 7. It is nearly allied to A. Jiector, D'Orb. ; but the ribs pretty 

 regularly divide into three, and not more, at the larger diameter, 

 though the smaller ribs are at first four times as many as the large 

 ones. 



Ammonites pectinatus, Phillips. 



This I think to be the same as A. Bevillei, De Loriol, because the 

 young of the latter has as numerous ribs as the former, according to 

 the description, and a specimen showing the peculiar proboscis-like 

 form of the aperture had also fine ribs on the inner whorls. Never- 

 theless A. pectinatus acquires a size larger than any known speci- 

 mens of A. Devillei without showing the changes. If they be 

 distinct, then hoth species occur in the Swindon Sands. 





