370 BlUTrSH GRAPTOLITP]S. 



1897. Linoyrajifas Nih.'^oni, Freeh, Loth. Gj )gii., vul. i, pi., iii, p 662, fig. 218. 



1899. Mono(jrapius Nilssoni, Poriier, Ktule.s sur les G-raptolites de BjIiuius, pt. iii, sect, b, [>. 7, pi. 

 xvii, figs. 1,2, 7. 



1900. MonofjvaiAus Nilssonl, Wood, Quart. Jouru. Geol. Soc, vol. Ivi, p. 4S2, text-fig. 24, pi. x.w, 

 figs. 28a, 28h. 



Polypary several cm. in length, straight distallj, but with gracef^ul doable 

 curvature in the proximal portion; slender, never exceeding 1 mm. in breadth. 

 Thecce eight to nine in K) mm. ; simple tul)es with slight tendency to sigmoid 

 curvature, about 2 mm. in length, four to five times as long as wide, over- 

 lapping ahout one-third their length, inclination low ; apertural margins 

 normal, those of straight distal portion nsuall j at right angles to the direction 

 of the polypary. 



Description. — The form of the polypary with its straight distal portion, concave 



middle portion, and convex proximal termiiudion, is 



PiOK. 2il rt— c. — Monogroptus Nilssonl t ■ t ^ ■ ■ t. iit 



(Barr.). highly characteristic, it is extremely slender at 



\~-f the proximal end, measuring only "2 mm., and then 



V ! /s . . . 



■'\^ 1^7 widens gradually and persistentl}' till the maxiinum 



|i:y breadth of 1 mm. is attained. 



llp;^ Tlie sicula is small, but distinct; it has a length 



[i^'^, of about 1"5 mm., and the first theca arises near its 



\). Mij '[ V apex, so that the apertural })ortion of the sicula 



J; 1^', alone forms the termination of the polypary. 



.W '(i The thecse are simple straight tubes overlapping 



,u ( /^i the merest fraction of their leno-th in the convex 



'^ --^ proximal portion of the polypary ; luit with the 



^ " beginning of the concave portion, a slight curvature 



rt. Proxinuil end, sliowin<y sicula. ■, ■. ■ ,■, -,, t ii • • 



Fi^^lued Quart. Jourii. Geoi. Soc, makcs its ai)pearance in the walls, and this is even 



vol Ivi, p. 482, fi<r. 24 «. Mont- i j.^ • j1 i ■ l i- T i l j. rm 



gomery Koad. n.'ir Welshpool- better sccn HI the straight distal part. Iheaper- 



.. Tiiro^;;;^.Sr^i^.t£n J «:1; ^ural margins are even and normal, but while those 



^'»'\^P'v-vv^?ri^'«^''i"™'' "^' ^'""''^ of the concave portion nsuall y lie somewhat obliciuely 



or 11. XaaVII, hg. la. ^ "^ i J 



c. Distal thecal Enlargement of part to the general direction of the i)olyi)ary, those of 



ol Plate XXXVII, fig. 1 c. ^. . 1 J 1 .; ' 



the straight distal part are approximately at 

 right angles, though not invariably so. 



Affinities. — The nearest relation of ]\f(iii(i(j. Ailxsun'i is nndou1:)ted]y Ci/rtoij. 

 CarriUhersi of the Upper Wenlock Beds, fragments of which are indistinguishable 

 from similar fragments of M. Nilssonl when both are similarly preserved, the 

 only distinguishing feature being the presence of branches in the Gijrloijniptas 

 form. 



Horizon and Loculltles. — Lower laidlow Shales (/one of M. Nilssonl). 



Lake iJlslrkt : Moughton Whetstone Hole, Cruinmackdale. Walsh Borders: 

 Montgomery Road; River Irfon near liuihh ; Vicarage Road, Builth; Old Dingle 



