Cretaceous and Tertiary Cirripedes. lf^7 



surface the occhident edge is very broad and flat, and is 

 widest at a point well al)ove the ])it for the adductor muscle, 

 M'here it is more than lialf tlie width of the valve ; au almost 

 flat triangular portion of tlie valve near the tergal margin, 

 bounded by the raised inner occhident edge, is marked with 

 growth-linos, and this part served for the reception of the 

 scntal angle of the tergiun ; the adductor muscle pit lies 

 ])elow the inner occludent edge, but above the |)it there is a 

 comparatively wide sloping portion of the v.Jve between it 

 and the triangular portion which received the tergum. 



Terguin (PI. VII. fig. 3) subrhomboidal, moderately convex 

 transversely, with a straight steep-sided ridge, much narrower 

 th;in that of the scutum, extending from the apex to the 

 basal angle, where it is produced ; apical portion scarcely 

 curved towards the scuta. The apico-basal ridge is situated 

 rather nearer to the tergal lateral margin, and where crossed 

 by the transverse ridges is somewhat raised. Upper carinal 

 margin convex, nearly straight, and about the same length 

 as the scutal margin ; occludent margin convex and of about 

 the same length as the lower carinal margin. A compara- 

 tively wide portion of the valve along the occludent margin 

 is slightly raised and rounded, and slightly protuberant 

 at the scutal angle; the raised portion is followed by a 

 depression from which the valve rises to meet an indistinct 

 ridge or fold in the valve extending from the apex to about 

 the middle of the scutal mai'gin. On the inner surface a 

 considerable ])ortion of the valve at the inner occludent and 

 upper carinal edges is flat and marked with growth-lines^ 

 the inner occludent edge being the narrowest. 



Upper latus unknown. 



PycnoJepas scularis, sp. n. (Plate VIII. figs. 7-10.) 



Diagnosis. Upper whorl of valves transversely and longi- 

 tudinally ridged ; the transverse ridges are produced into 

 sharp spines, where they are crossed by longitudinal ridges. 

 Scutum triangular, with no apico-basal ridge, and growth- 

 lines not upturned on the tergo-lateral half of the valve. 

 Upper latus long and narrovv. Tergum unknown. 



Material. A right scutum, two rostra, and an upper latus. 



Holotijpe. The rostrum (PI. VIII. fig. 7). 

 . Horizon and locality. Cenomanian, Chalk Marl : near 

 Cambridge. 



Measurements. This species is one of the smallest of the 



