200 



BRITISH GRAPTOLITES. 



1877. Climacograptus coelatus, Lapwortli, G-rap. Co. Down, pi. vi, fig. 39. 



1886. Glimacograjptus coelatus, Lapwortli, Trans. Roy. Soc. Canada, sect, iv, p. 167. 



Figs. 130 a and b. — Climacograptus 

 antiquus, Lapw. 



. Typical specimen showing basal 

 spines and long virgella, surrounded 

 partially by a membrane. On same 

 slab as PI. XXVII, fig 4 a. 

 Proximal end showing stout tubular 

 spines. Enlargement of part of 

 PI. XXVII, fig. 4 d. 



Figs. 130 c and d. — Climacograptus 

 antiquus, Lapw. 



e. Distal thecae showing their typical 

 form. Enlargement of part of PI. 

 XXVII, fig. 4 d. 



d. Distal part of polypary showing 

 growths on the distal prolongation 

 of the virgula. Oak Wood, Pontes- 

 ford. Coll. Lapwortli. 



Polypary 3 — 5 cm. long, with an approximately 

 uniform width of 2*5 mm. for the greater part 

 of its length. Sicula imbedded, virgella long ; 

 virgula conspicuous and of considerable 

 length. Thecse eleven to nine in 10 mm., 

 basal ones with spines, length 1*5 mm., over- 

 lap one-third, apertural margins slightly 

 introverted, situated in conspicuous elliptical 

 excavations occupying one-fourth to one- 

 fifth of the breadth of polypary and one- 

 third of its ventral margin. 

 Description. — The proximal end is rounded, and 

 the polypary measures 1 mm. in breadth, widening, 

 however, to 2'5 mm. within the first cm. of its 

 extent. The virgella is occasionally partly enclosed 

 within a membranous tube similar to that found in 

 Gl. caudatus, but the proximal tapering of the 

 polypary so noticeable in that species is here absent. 

 The two proximal thecse occasionally bear a stout 

 spine in the middle of the free straight part of the 

 outer wall. 



Affinities. — Gl. antiquus recalls Gl. (?) coelatus in 

 many respects, especially as regards its general 

 form, but it differs in the characters of its thecse. 



Horizon and Localities. — Glenkiln Shales. Llan- 

 deilo. 



N. Wales : Ty-Obry ; Tiddyndicwm. 8. Scot- 

 land: Dobb's Linn; Glenkiln Burn; Craigrnichan 

 Scaurs ; Berrybush Burn ; Kirkmichael Burn ; 

 Black Linn ; Penwhapple Glen. N. Ireland : 

 Ballygrot ; Coalpit Bay. S. Shropshire : Oakwood, 

 Pontesford. 



Associates, etc. — Gl. antiquus occurs in the Glen- 

 kiln Shales associated with Didymog. superstes and 

 Gl. (?) perexcavatits. 



The best specimens (including the type) are in 

 Lapworth's Collection. 



