234 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Telson expanded and cordate at base, the broadest portion being 

 less distant from the insertion than one-third the entire breadth. 

 From thence the tail-joint is regularly acuminated, the length being 

 only two and a half times the breadth. The edge is crenato-serrate 

 like the last. We have only the flat under surface. 



Locality. — With E. megatons at Ludlow. 



E. LINEARIS, spec. nov. Plate X. figs. 15, 16. 



As this occurs generally in a lower stratum (Upper Ludlow Eock) 

 than the last, it is little likely to have any relation to that species, 

 though the differences are such as might be due to sex. If, how- 

 ever, E. megalops and E. acuminatus be one species, E. linearis must 

 rank as distinct. The telson, the only part preserved, is greatly more 

 elongated than in the other forms. 



Telson linear, lanceolate, nearly five times as long as wide ; the 

 base very Kttle expanded ; broadest near the point of insertion, or 

 rather parallel-sided for a short distance, and then attenuated. A 

 strong median cariaa runs the whole length, elevated iuto a steep 

 ridge near the origin of the joint ; and the edge is so faintly crenate 

 as to appear smooth to the naked eye. 



Fig. 15 shows a broader telson, from the same bed, and it most 

 probably bears the same relation to E. linearis that the last-de- 

 scribed species does to E. megalops. From analogy we must suppose 

 the broader tail-joint to belong to the female, and the narrower one 

 to the male. 



Locality. — The Upper Ludlow Rock of Ludlow, and the Downton 

 Sandstone of Kington, Herefordshire. 



E. ABBEEViATus, spcc. uov. Plate X. fig. 18. 



A thoroughly distinct species, yet with very similar characters to 

 those of E. acuminatus, as if the telson of that species had been 

 greatly abbreviated. 



Telson broadly trigonal at base, — ^forming a nearly equilateral tri- 

 angle, of which the smooth thickened base forms one angle ; the 

 sides expand with a curved outline for about half the length of the 

 joint, then suddenly contract and form a narrow, acuminate, serrated 

 point. 



We have only the under surface ; the upper was probably keeled ; 

 the lower shows a faint longitudinal elevation proceeding from the 

 thick base to the point. The serrse on the edge are very prominent. 

 Length -^-^ inch, width -^ inch. 



Locality. — Downton Sandstone of Kington, Herefordshire. 



E. CHAETARIUS*, SpCC. nOV. 



I subjoin a diagnosis of this small form, mentioned above, and 

 which will hereafter be figured in one of the Decades of the Geolo- 

 gical Survey. 



* Aquila chartacea, a Roman boy's kite, which the fossil much resembles. 



