GLOSSOGRAPTUS. 



311 



\1 



i0 



m 



n 



^ 





enclosed in a membrane which gives an appearance of undue breadth (PI. XXXIII, 

 tigs. 2/,)). 



Affinities.— The affinities of this, the most abundant of all the British forms 



of the Glossograpti, are decidedly 



Figs. 205 d—f.— Glossog raptus Hincksii (Hopk.). , 



with the American form referred 

 to Glossog. ciliatus (Emmons) by 

 Ruedemann (' Graptolites of New 

 York,' pt. 2, pi. xxvi, figs. 1 — 5 ; pi. 

 xxvii, figs. 1 — 4), of which it may 

 prove to be merely a variety, or at 

 all events a vicarious representative. 

 The British form may, however, be 

 distinguished by the narrower and 

 more rounded form of the base, the 

 more closely-set tbecas (especially in 

 the proximal region), and the stouter 

 character of the spines. From var. 

 fimbria tit s it differs in the larger and 

 more robust form of the polypary ; 

 and from Glossog. acanthus it may 

 readily be separated by the shape of 

 the polypary and the character of the 

 spines. 



Horizon and Localities. — Llandeilo 

 and Bala (Glenkiln and Lower Hartfell 

 Shales). 



South Scotland : Wanlock Water, 

 Wanlock Head ; Birnock Water ; 

 Trowdale Glen, Castle Douglas ; 

 Hartfell Spa ; Dobb's Linn, etc. 

 Ireland : Coalpit Bay, Donaghadee ; 

 Ballygrot, Co. Down. 



Associates, etc. — Glossog. Hincksii 

 is an abundant fossil in one bed in the 

 Glenkiln Shales at Wanlock Water, 

 Wanlock Head. It is associated at 

 this horizon with Nemag. gracilis and 

 Didymog. superstes, etc. It is also 

 fairly abundant near the base of the 

 Hartfell Shales (zone of Climacog. 

 Wilsoui) at Hartfell Spa, and Dobb's Linn in the Moffat country, where it is 



/ 



d. Distal end, sealariform view, showing' apertures of theea 1 



and strong- septal spurs. 



e. Distal end, subscalariform view, showing both apertural 



and septal spines and also one septal strand clearly 

 distinct from virgular tube. Enlargement of part 

 of PI. XXXIII, fig. 2 i. 

 /. Specimen with test almost removed, showing lists and 

 spinous processes. Hartfell Spa, Hartfell Shales (zone 

 of Climacog. Wilsoni ?). Coll. Geol. Survey of Scotland. 



