430 



BRITISH GRAPTOLITES. 



Associates, etc. — Monog. irfonensis occurs in the zone of Gyrtog. Lundgreni, 

 associated with C. Lundgreni, and M. Flemingii var. compactus ; it is a rare 

 species. 



Collections. — Watney and "Welch, Elles. 



IV. A. 2. (a) : Monograpti in which the thecas are uniform and the polypary has 



dorsi- ventral curvature. 



Monograptus flexilis, Elles. Plate XLIII, figs. 4 a — e. 



1900. Monograptus flexilis, Elles, Quart. Journ. G-eol. Soc, vol. lvi, p. 407, fig. 18. 



Polypary long and flexed, curvature variable, but always strongly reflexed 

 proximally, widening gradually to a maximum breadth of 2 mm. Sicula 

 very distinct, furnished with an exceedingly long virgella. Thecas twelve 

 to nine in 10 mm., of the general type of those of M. Flemingii, but 

 with a somewhat shorter beak, which occupies a smaller fraction of the 

 breadth of the polypary. 

 Description. — The polypary may attain a length of fully 22 cm. and in some 

 cases makes a more or less complete 2-like curve, but smaller individuals are of 



commoner occurrence. The polypary 

 Fig. 293.— Monograptus flexiiu, Elles. itself widens gradually from an initial 



breadth of about 1 mm. to a maximum 

 of about 2 mm., which is attained from 

 1*5 cm. to 2 cm. from the proximal 

 end. 



The sicula is broad and measures 

 nearly 2 mm. in length, reaching 

 almost to the level of the aperture of 

 th. 2. The long and stout virgella 

 may be as much as 2'5 cm. in length, 

 continuing the line of the polypary by 

 that amount. 



Affinities. — Monog. flexilis agrees 

 with all the varieties of M. Flemingii in the general characters of its thecae (though 

 the retroversion of the apertural region is somewhat less pronounced), but the con- 

 spicuously flexed polypary and the lengthy virgella make it readily distinguishable. 

 Horizon and Localities. — Wenlock Shales (zone of Gyrtog. Linnarssoni). 

 Wales: Slate Quarries, Moel Ferna; Stream S. of Tomen-y-Meirw, Dee Valley. 

 Lake District: Shap Wells; Rawthey Bridge, near Sedbergh ; Middle Gill and 



Complete specimen, showing 1 sicula and virgella. Near 

 Gill, C'autley, Yorkshire; Wenlock Beds. Coll. Miss 

 Welch. 



