406 



BEITISH GEAPTOLITES. 



Monograptus incommodus, '^I'ciriKjiiist. Plate XL, figs. 1 a—e. 



1809. Monographts incommodiis, Tnrnqiiist, Monograptidre of Scaniaii Fcmirih's Beds Liinds CJiiiv. 

 Arssk., vol. XXXV, pt. 2, no. l,p. 11, pi. ii, figs. 1 — 5. 



FjGS. 272 a — e. — Monocjrapl'us incommo- 

 dus, Tornquist. 





lit II 



Polypary long and sleiuler, with irregular curvature, Avidening from a slender, 

 slightly arcuate, or straight proximal portion to a flexed distal portion with 

 an avei'age breadth of "6 mm. Thecre eight to seven in 10 mm., inclined 

 at a very low angle and overlapping one-third to one-half their length ; 

 apertural margins even and slightly introverted. 



Description. — The polypary is very long, slender 

 and flexed, the curvature being, however, generally 

 dorsal ; the proximal end is very slender (though 

 not so slender as in M. Sandersoni), but widens 

 fairly rapidly to the maximum breath of '5 mm. 



The sicula has a length of fully 3 mm., and 

 reaches to the level of the aperture of tli. 1 which 

 arises from a point about half-way along its length. 

 The thecse resemble those of M. Sandersoni, 

 but the introversion of the apertural margin appears 

 to be slightly less marked. 



Affinities. — Movog. incommodes is clearly related 

 most closely to M. Sandersoni ; but while the curva- 

 ture in M. incommodus is mainly dorsal or irregular, 

 in M. Sandersoni it is invariably ventral ; and the 

 ])olypary is rather more robust at the proximal end. 

 Horizon and Localities. — Llandovery (Birkhill 

 Shales), zone of M. ci/jdins. 



S. Scotland : Dobb's Linn ; Belcraig Burn, etc. 



Lalce District .- Skelgill. Ireland : Coalpit Ba}^ 



Donaghadee ; Mill Sluice below Slate Quarry, 



Pomeroy. Wales: Rheidol Gorge, Pont Erywd; 



Conway ; Pary's Mountain, Anglesea ; Llany- 



stwmdwy, near Criccieth. 



Associates, etc. — Movog. incommodus is a fairly common fossil in the zone of 



ill. cj/pliKs ; it is commonly associated with Monog. cijplius, M. rerolutiis, M. 



Sandersoni, M. atavns, various Dimorphograpti, and Climacog. medins. 



Collections. — Sedgwick Museum, Geological Survey of Scotland, Geological 

 Survey of England and Wales, Fearnsides, Jones, Lapworth, and the Authors. 



11 



d 



a. Proximal end, showings sieiila. Dobb's 

 Linn ; Birkl)ill Shales. Coll. Lap- 

 worth. 



6. More distal thecae. Part of specimen 

 on same slab as Fig. 272 a. 



c. Theca; preserved in relief. Llanys- 



tvvmdwy, near Criccieth ; Llando- 

 very beds. Coll. Fearnsides. 



d. Theca;, showing appearance of intro- 



verted apertural margins; ini'elief. 

 Enlargement of part of PI. XL, 

 fig. 1 b. 



e. Distal thecae, compressed. Enlarge- 



ment of part of PI. XL, fig. 1 c. 



