402 BRTTfSH GRAPTOLITES. 



Tlie tliecfe of the extreme proximal portion show a tendency to ogee curvature 

 in tlieir 'walls and appear to liave retroverted and spined apertural margins. The 

 spines of tlic mature distal thecne seeni to be mesial in position, but this is possibly 

 deceptive and due to compression, as their apparent point of origin is by no means 

 constant in different individuals. Although in most cases only one spine is visible 

 on each tlieca, yet it would ap})ear from certain specimens (fig. 208 c) that a pair 

 of s]nnes is really present. 



Affinities. — AFoikkj. IcintivarduioisiH is a most characteristic species, which, how- 

 evei', is closely allied to M. cliimxra and its varieties; the proximal thecal 

 are certainly similar, but the spines of the distal tliecte, so far as can be deter- 

 mined, appear to be different in position. 



Hori::()ii and Localities. — Ludlow Shales (Aymestry Limestone), zone of M. 

 Jciiiticardinnisis. 



Tjiidluiv District : Churcli Hill, Leintwardine; Adferton ; Trippleton; Aymestry; 

 Vinuall; Ludlow Road; Broxton and Burton. WelsJt, Borders: Lettygynfach, 

 Long Mountain; Aberedw, near Builth ; Presteign, Old Radnor; Launwell 

 Dingle. Lahe District : Near Knock, etc. Dee Valleij : Pen-y-vivod ; Llantisilio 

 Road. 



Collections. — Sedgwick Museum, Fearnsides, Lapworth, and the Authors, etc. 



Var. incipiens, Wood. Plate XXXIX, figs. 9 a—d. 



1900. Mono(jraptiis leintivarJinensis, vnr. incipiens, Wocxl, Quart. Juuru. Geol. Soc, vol. Ivi, p. 474, 

 pi. XXV, figs. 22 A, B. 



ViG.2Q<;).~Monoora]plnslcmtwardin6nsis, rpj^j^ variety of Moitihl. h'iltf tCa rd iiwnsis aoTCCS 



var. i7icipiens, Wood. ,/ i/ o 



with the typical form in general, except that it is 

 somewhat broader (2 — 2''S mm.) and longer, and 

 that only its proximal thecee are spined. It Ijears 

 the same relation to the typical form that A^ar, 

 semi spin OS as does to M. chiuisera. It has never been 

 found, hitherto, in association with the typical form, 

 and may bo merely a local variant. 



Horizon and Localities. — Lower Ludlow Shales 

 (near summit). 



^\\ Welsh Borders: Montgomery Road; Rose and 



Crown Inn, Long Mountain; Lower Winnington, 



Complete sijecimeii, showing sicula. . . . . 



Montgomery Road; Lower Ludlow etc. Lake District: Tebav Gill, Baiinisdalc. 



Shales. Coll. Wood. . ... 



Associates. — Var. mcipie?is seems to occur at a 



ji 



rather lower horizon than the typical M. leinttvardinensis; its only known 

 associate is M. cf. ultimus. 

 Collection. — ^AVatts, Wood. 



