100 



PROCEEDINGS OF THE 



Locality and Horizo?i.—La\v Quarry, near Dairy, as before. 

 Collections. — J. Bennie, J. Armstrong, J. Smith, &c. 



Chitonellus (?) KirJcbyanus, sp. nov.— (PL II., figs. 14-22.) 



>Sp. Char. — Anterior plate conoid, except on one side, which is 

 partially truncated. Anterior margin rounded ; posterior forming an 

 arched re-entering angle ; postero-lateral angles rounded. Apex ele- 

 vated, sub-central to posterior in position, and when so, overhanging 

 the posterior margin. The plate is more or less arched along the 

 middle line ; from the apex to the postero-lateral angles two ridges 

 proceed, which enclose a small obliquely truncated triangular 

 space ; two faintly-marked diagonal ridges proceed from the apex 

 forwards, one on each side. Inserted portion of plate forms a 

 small unornamented margin round the edge of the plate, broader 

 on the anterior. 



Second plate (?) quadrate in outline, almost as broad as long, 

 very much arched. Median line obtusely carinate. Anterior 

 margin a little concave in the centre, rounded at the sides; 

 posterior and posterior end as in the anterior plate. Apex ter- 

 minating the central keel, somewhat overhanging. The inserted 

 part of the plate forms a band round the edge as usual, the broadest 

 portion being at the rounded anterolateral angles. 



Intermediate plate elongated longitudinally, and strongly arched ; 

 the apex placed at the posterior end of the arched keel is a little 

 elevated, and the dorsal line concave. Anterior margin rounded at 

 the sides, and much excavated in the middle line; posterior margin 

 similar, but the excavation shallower; as in the former plates a 

 small obliquely truncated area is formed at the posterior end by 

 two angles from the apex to the postero-lateral angles. A faint 

 diagonal sulcation passes from the apex forwards on each side 

 defining, indistinctly, the dorsal and lateral areas. Exposed sur- 

 face of the plate small, as compared with the inserted portion, 

 more or less cordate in outline, and occupying the posterior end of 

 the plate ; the inserted margin is broadest forwards, and has a few 

 indistinct radii on the surface. 



The posterior plate is narrow and much elongated longitudinally, 

 but patelliform in the hinder portion. Anterior margin excavated 

 in the middle, projecting forwards at the sides ; posterior margin 

 rounded. Middle line arched, carinate and concave, terminating in 

 the elevated apex, which is within the margin. The posterior end 





