436 



BRITISH GRAPTOLITES. 



Fig. 299. — Monograpius Jaelceli, Perner. 



Polypary several cm. in length, conspicuously curved, widening steadily till the 

 maximum breadth of 3 mm. is attained, and thereafter of approximately 

 uniform breadth. Thecae nine in 10 mm., of the general type of those of M. 

 priodon, but with barely one-half of the theca involved in the short hook, 

 which only occupies one-fifth of the total breadth. Overlap two-thirds of 

 total length. 

 Description. — The polypary always shows pronounced curvature, but this is 

 variable both in amount and in direction, the thecse being borne usually on the 



convex, though occasionally on the concave margin. 

 The width in the distal portion of the polypary is 

 uniformly about '■] mm. The proximal portion is at 

 present unknown in Britain. 



Affinities. — The theca of Monog. Jaelceli is very 

 like that of M. priodon in its general shape, but the 

 hook is much shorter and less of the theca is 

 involved in it. The polypary, however, in the 

 former is curved instead of being straight as in the 

 latter. 



Horizon and Localities. — Wenlock Shales (zone 

 of Cyrtog. Linnarssoni). 



]Vi-hh Borders: Builth Road; Coppice House, 



Distal thecae. Enlargement of pari of near MiddletOWU, Long Mountain. 



Associates, etc. — Monog. Jaelceli seems to be 

 characteristic of the Middle Wenlock Shales, in which it is found with Gyrtog. 

 Linnarssoni and M. vomerinns. 



Collection. — Sedgwick Museum. 



Monograptus gemmatus (Barrande). Plate XLIII, figs. 5 a — e. 



1850. Rastrites gemmatus, Barrande, G-rapt. de Boheme, p. 68, pi. iv, fig. 5. 



1868. Rastrites capillaris, Carruthefs. Geol. Mag., vol. v, p. 126, pi. v, tig. 16. 



1872. Graptolithus attenuatus, Hopkinson, Geol. Mag., vol. ix, p. 503, pi; xii, fig. 3. 



1876. Rastrites capillaris, Lapworth, G-eol. Mag. [2], vol. iii, p. 31-1, pi x, figs. 4 a, b. 



1876. Monograptus attenuatus, Lapworth, G-eol. Mag. [2], vol. iii, p. 317, pi. x, figs. 9 a — cl. 



1897. Monograptus gemmatus, Perner, Grapt. de Bohcme, pt. iii a, p. 10, pi. xi, figs. 30 — 32. 



Polypary very slender and almost thread-like, arcuate, or nearly straight, 

 widening from the finest thread in the proximal region to a maximum 

 breadth of about '5 mm. Thecal- generally on the convex side, six to nine 

 in 10 mm., long narrow tubes with the extreme apical region isolate, 

 twisted and retrovorted to form a short but distinct hook occupying 



