472 MISS E. M. E. WOOD ON THE LOWER LUDLOW [May 1 9OO, 



detecting the true form of the theca and the position of the apertural 

 spine, but the English examples are so indifferently preserved that 

 it is only possible to infer their characters. When the thecse are 

 preserved in true profile, the spine arises slightly above the centre 

 of the lateral wall of the aperture, and is not a prolongation of the 

 interthecal wall (see fig. 18 a, p. 473), as is the case in Monograptus 

 hint war dinensis. This, then, would probably be the true position 

 of the spine if the theca were in relief, and might produce a certain 

 angularity in the form of the theca ; indeed, in one specimen, 

 preserved so that the apertures face the observer, one or two of 

 the thecae appeared to be hexagonal in shape. The spines of the 

 proximal three or four thecae are seldom seen in true profile, and 

 present much the same appearance as those of M. colonics ; but it 

 is probable that there is no essential difference between their 

 original position in the proximal and that in the distal parts of the 

 polypary. The various positions that the spine assumes under 

 different conditions of preservation may be best seen from the 

 figures. 



Foreign Localities. — Bohemia (Hinter-Kopanina). (Ee 2.) 



British Localities. — Ludlow district (Elton-Ludlow Road, 

 Elton Lane) ; Builth district (Aberedw Hill) ; the Long Mountain 

 (north side). 



Horizon. — It occurs typically in the M.-scanicus zone, but is 

 also found in the M.-Nilssoni zone. 



Associates. — M. scanicus, M. Roemeri,M. dubius, M. bohemicus, 

 and M. JS'dssoni. 



Var. Salweyi (Hopk. MS.). (PI. XXY, figs. 19 a & 19 b and 

 text-fig. 18, p. 473.) 



1880. Monograptus Salweyi (Hopk. MS.) Lap worth, Ann. & Mag'. Nat. Hist, 

 ser. 5, vol. v, p. 150 & pi. iv, tiers. 2 a-b. 



M. chimcrra var. Salweyi was originally named by Mr. Hopkinson 

 as a distinct species, and his type-specimen, which shows the distal 

 end only, was figured by Prof. Lapworth. Prom numerous specimens 

 of this form, collected by me from Mr. Hopkinson's type-locality of 

 Stormer Hall, near Leintwardine, I have been able to complete the 

 description of the whole polypary. 



Although no other specimen was found showing the extremely 

 long distal prolongation of the virgula, so characteristic of Mr. Hop- 

 kinson's type-specimen, there is no doubt as to its identity, for it is 

 the dominant species at this locality. M. Salweyi in its typical 

 form is a well-marked variety of M. chimcera (Barr.), and is distin- 

 guished from it by the following peculiarities : — 



(1) Polypary seldom exceeding 12 # 7 mm. ( - 5 inch) in length, and attaining 



a maximum width of 1*6 mm. (06 inch) ; 



(2) Margins of polypary parallel except at the proximal extremity, the 



increase in width taking place within the length occupied by the 

 first five or six thecse ; 



(3) Polypary straight throughout; 



(4) Virgula prolonged distally for a considerable length ; and 



(5) Thecal apertural spines longer and more slender. 



