214 



BRITISH GRAPTOLITES. 



-Climacograptustuberculatus, 

 Nich. 



in the scalariform view of the polypary, and appear 

 to be the thickened edges of the apertural margins 

 which tend to be produced into short curved spines. 

 This feature is conspicuous at the proximal end but 

 is less marked at the distal extremity. 



Affinities. — Exception being made of the tubercles 

 and the basal spines, the species resembles CI. scalaris 

 in form, but the presence of these features should 

 suffice to distinguish it in all cases. From CI. 

 bicornis it differs in the characters of the spines and 

 also in the number of thecae in the same unit of 

 length. 



Horizon and Locality. — Highest Hartfell Shales 

 (zone of Dicellog. anceps) and base of Birkhill Shales (zone of Gephalog. acuminatus). 

 S. Scotland : Dobb's Linn. 



Associates, etc. — CI. tuberculatus is a rare fossil in the beds at the junction of 

 the Hartfell and Birkhill Shales in Dobb's Linn. It is associated with CI. scalaris 

 and Dimorphograptus sp. 



The type specimens are in the British Museum (Natural History). 



b. Distal thecffi showing form of aper 

 tures. Ibid. 



