152 BRITISH GRAPTOLITES. 



included two different species under this name. Figs. 28 and 29 represent a form 

 with strong concave ventral curvature of its stipes throughout, but his figs. 30 and 

 31 are similar to those which are now generally recognised as the typical 

 D. Forchammeri. 



Affinities. — D. Forchammeri shows resemblances toD. comjplanatus in its general 

 form, but it differs in the character of the proximal end and the introversion of 

 its thecal apertures. The proximal extremity is similar in some respects to that 

 of D. elegans, but the curvature of the stipes serves to distinguish the two species. 



Horizon and Localities. — Grlenkiln and Hartfell Shales (especially the zone of 

 Dicranog. Clingani). 



S. Scotland.— Moffat Area : Dobb's Linn; Hartfell; Syart Law; Moffat Water; 

 Mount Benger Burn. Girvan Area : Tralodden ; Ardwell Bay, etc. Wales. — 

 Cynghordy, Derwendeg, Tiddyndicwm. Ireland. — Kilmacreagh, Co. Clare; 

 Carnalea ; Ballygrot ; Coalpit Bay. 



Associates, etc. — D. Forchammeri is a rare fossil in the upper zones of the Glenkiln 

 Shales of S. Scotland and Wales, where it occurs associated with Nemag. gracilis 

 and Dicellog. sextans ; it is, however, very common in the Hartfell Shales, especially 

 in the zone of Dicranog. Clingani, where it occurs associated with Leptog. flaccidus, 

 Dialog, foliaceus (auct), D. truncatus, and other forms. It has also been found 

 in the zones of Glimacog. Wilsoni, and Pleurog. linearis. The best specimens are in 

 Lapworth's collection and in those of the Sedgwick and Natural History 

 Museums. 



Var. flexuosus, Lapworth. Plate XXII, figs. 2a— d. 



1876. Dicellograptus Forchammeri, var. flexuosus, Lapworth, Cat. West. Scott. Foss., pi. iv, fig. 90. 



In addition to the typical D. Forchammeri, a well-marked variety is occasion- 

 ally met with, in which the stipes are much narrower and are conspicuously 



flexed. They are only '5 mm. wide at their origin 



Figs. 95 a. — DiceUoiirarittm Forehnmmeri, -\ -, -, i -i , n mi • i 



var flexuosus, Lapw. and never exceed 1 mm. m breadth. The sicula 



is more conspicuous than that of the type form, 

 and is both longer and narrower. The apertural 

 excavation of the thecaa is relatively broad, generally 

 occupying about half the width of the stipe ; and 

 the spinous outgrowths from the walls of the distal 



a. Reverse view in low relief . Enlarge- ,i „ r n i i l xi j.1 j. • i 



ment of part of pi. xxii, fi g . 2b. thecas are more fully developed than m the typical 



% 



form. 



