f^ •7/'! 



HlMTISll (UlATTOJATES. 



Fios. 2iC> a — d. — Mo)ioiiraplHs niidus 

 (LapworUi). 





Description. — -Tlio [jolypary of JSIoikkj. luidns is usually straig'lit and rigid, 

 resemblino' that of M. jitriilniii, but it doc's not exceed 5 cm. in length. 



The sicuhi is fully 1 mm. in length, and extends up to the aperture of tli. 1, 

 which originates near its base. 



The thecal increase in length from 1'5 mm. proximally to 2 mm. distally, 



and the overlap increases from one-third to 

 one-half. They are simple sacculate tubes, 

 very bi'oad in proportion to their length, with 

 tlu'ir free ventral margni somewhat impressed, 

 producing a slight excavation. The average 

 inclination of the thec;\3 is high. 



Affinities. — In the form of the polypary 



Moiwg. nndns approaches M. jncalnm, but 



differs in liavins^ shorter and broader thecse 



J Y.fi [if •■' ^ with a ventral excavation. As respects the 



/ ^^ '■/'■■''^ ' £ thecfB Monuij. nndus api)roaches M. concinnux, 



but differs in havino- a straight polypary. 

 'V ^^' Ufw H Horizon and Locdlities. — Llandovery — 



Tarannon. 

 " ^ '■■ d /S'. /SVo/^ay/fL- Dobb's Linn; Belcraig Burn; 



a. Pi-dxiiiial end, showing' sicula, in low relief. _ 



Enlargement of part of PL xxxvii, Griestoii Quai'ry ; Broadmcadows, Glendearg, 



fig. 6 h. , . . 



h. Di.stai thec'f, in relief, showing ventral ctc. Wciles : Llaiiystwmdwy, near Criccictli ; 



excavation. Enlargement of part of ^. ^n -n- t i i • i-i -i 



ri. XXXVII, fig. (id. Uonway; iarannon Itiver ; Llanbrynmair Itail- 



r. Distal thcca; preserved as a cast. Diid. ,. , -.^ . t-, i t^- j ■ j. 



d. Distal theca;. compressed, showing their Way sectiou, ctc. ; i ont LrAvyd District. 



sliort and broad cliai-acter. Enlargement i • i , ir 7 • i l 



of part of PI. XXXVII, fig. G a. Assocudes, etc—Mouoij. nndns is a character- 



istic Gala-Tarannon species ; it is, however, 

 occasionally found in the highest Llandovery beds. It occurs with Monog. 

 Sedtjn-icl-li and M. tennAs at the Llandovery horizon, and with M. tnrricnlafns, 

 M. exhjnji^, M. (tiscns, M. Mnrri, M. (jrii'sionem^ls, and other forms in the Gala- 

 Tarannon beds. It is fairly abundant. 



Collertiuns. — Geological Survey of England and Wales, Lapworth and the 

 Authors. 



Monograptus dubius (Suess). Plate XXXVII, figs. 7 a—d. 



1850. OraptoUllms colonuif, Barraude, Grapt. de Bohcme, p. 4o, pi. ii, fiy. 5. 



18.51. GraptoUllivs duhius, Suess, Ueber JJiJlimisclie Graptolitlii'ii, Haidinger's Abhandl., vol. iv, 



pt. iv, p. 11-5, and pi. ix, figs. 5 a, 5 &. 

 1876. Mimograptus dubins, Lapworth, Gcol. Mag., dec. ii, vol. iii, p. 506, pi. xx, fig. 10. 

 1880. Monocjraptus serra, Hopldnson MS., Lapworth, Ami. Mag. Nat. Hist. [5], vol. v, pi. iv, figs. 6 r, J. 

 1883. Monograi>tus duhim, Tullberg, Sk^nes Graptoliter, pt. ii, Sv. Geol. Undersiikn, Sct. C, 



no. 56, p. -29, pi. i, figs. 28, 29, pi. ii, figs. 20, 21. 



