CLIMACOGRAPTUS. 



197 



-d. - Climacograplus super- 

 nns, sp. nov. 



b 



;■■■■■ 



!: 



Description. — The polypary is generally small, the increase in breadth takes 

 place within 5 mm. of the proximal end, but it is noticeable that the poly pan- 

 is often slightly wider at its extreme proximal 

 end than it is opposite the apertures of th. 2 1 and 

 th. 2 s , a fact which seems to be accounted for by 

 the presence of the sicula, which is broad at its 

 aperture, but tapers quickly in its apical region. 



The sicula is commonly situated somewhat 

 obliquely, and is often visible for only 0*5 mm. of its 

 extent ; th. I 1 originates at the top of the visible 

 portion, grows downward and then upward, giving 

 off a slender spine about 1 mm. in length from the 

 base of the upward growing portion ; th. I 2 grows 

 somewhat obliquely upward and outward from th. I 1 , 

 originating a similar spine from the base of its 

 upward growing portion. The virgella usually 

 appears as a medial excrescence between them. 

 Occasionally the whole proximal end appears to be 

 enveloped in a disc. 



Affinities. — In its general form and the characters 

 a. small specimen, with proximal end f the thecse, and above all in the presence of the 



enclosed in a small disc. On same _ l 



slab as fig. 129 c basal spines, CI. supemusbesbrs obvious resemblance to 



Gl. bicornis ; it is, however, a much smaller form, is narrower, and has the thecae 

 more closely set, its spines are also more slender than those of Gl. bicornis; it is, 

 however, not impossible that it is the dwarfed survival of that species. 



Horizon and Locality. — Upper Hartfell Shales (confined to zone of Dicellog. 

 anceps). 



S. Scotland.— Dobb's Linn ; Hartfell, etc. 



Associates, etc. — Gl. supernus is a fairly common fossil in the Dicellog. anceps 

 zone, especially at Dobb's Linn, where it occurs on the same slabs as D. anceps. 



Collection. — The Authors. 



a. Proximal end, obverse view, showing 



small virgella. Enlargement of 

 part of PI. XX VI, fig. lib. 



b. Reverse view, showing long spines. 



Dobb's Linn, Upper Hartfell Shales 

 (zone of Dicellog. anceps). Coll. 

 Wood. 



c. Obverse view, showing sicula. Ibid. 

 Coll. Elles. 



Climacograptus Wilsoni, Lapworth. Plate XXVI, figs. 12 a — d. 



1876. Climacograptus Wilsoni, Lapworth, Cat. West Scot. Foss., pi. ii, fig. 46. 



1877. Climacograjdus Wilsoni, Lapworth, Grap. Co. Down, Proc. Belfast Nat. Field Club, p. 140, 

 pi. vi, fig. 40. 



Polypary 2 — 6 cm. or more in length, increasing gradually in breadth up to a 

 maximum of 2'5 mm., which is then maintained up to the distal extremity. 

 Sicula 2*5 mm. in length, proximal end commonly furnished with a con- 

 spicuous vesicle of elliptical form. Thecae twelve to eighl in 10 mm., 

 overlapping one-third to one-half their length, with slightly curved sub- 



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