68 



M. RUTA 



Fig. 7 Juliaecarpus milnerorum gen. et sp. nov. Late Ordovician, Upper Ashgill, Rawtheyan, Upper Ktaoua Formation, Morocco. Reconstruction of 

 external and internal aspects of styloid and of a proximal ossicle. A, right lateral view of styloid. B, anterior view of styloid. C, ventral view of styloid 

 (much reduced with respect to A and B). D, right lateral view of ossicle. E, posterior view of ossicle. F, dorsal view of ossicle. 



well developed anterior spike (Fig. 7A-C; PI. 2, fig. 3: PI. 3, figs 1, 

 3-4; PI. 5, figs 1, 3-4; PI. 7, fig. 6; PI. 8, figs 1-2). The posterior part 

 is gently arcuate ventrally in lateral view and is about as long as wide. 

 Its ventral surface is approximately semicircular in cross-section. Its 

 lateral surfaces are subparallel and slightly convex to flat in their 

 uppermost part and decrease rapidly in height posteriorly converg- 



ing into a broadly semicircular posterior margin. The latter forms the 

 postero-ventral boundary of a circular excavation which occupies 

 the posterior half of the styloid. The excavation lies on an oblique 

 plane oriented at an acute angle with the horizontal plane. 



The height of the spike is slightly greater than the total length of 

 the styloid. The spike is gently curved backward near its apex, 



PLATE 8 



Juliaecarpus milnerorum gen. et sp. nov. Late Ordovician, Upper Ashgill, Rawtheyan, LIpper Ktaoua Formation, Morocco. All latex casts coated with 

 ammonium chloride. 1, EE 3101, x 20; close-up of aulacophore; note partly damaged styloid spike. 2, EE 3070, x 20; posterior half of ventral aspect of 

 theca and poorly preserved styloid and ossicles. 3, EE 3178, x 8; almost complete, slightly compressed theca of an individual in dorsal aspect (bottom end 

 of photograph), poorly preserved theca of a second individual in dorsal aspect (centre) and isolated plate M'^. 



