TAB. I. 



Fig. la, Balanus tintinnabulum, nat. size; small specimen. 



lb, ,, ,, rostrum, internal view of, large specimen, nat. size. 



lc, Id, „ „ scutum and tergum, internal views of, from recent spe- 



cimens, the opercular valves not having been found 

 fossil. 

 Fig. 2a, Balanus calceolus, engraved from a recent specimen, the single fossil having been 



injured during examination. 

 2b, 2c, ,, „ scutum and tergum, internal views. 



2d, Spur of tergum, variety : all from recent specimens, the opercular valves not 

 having been found fossil. 

 Fig. 3a, 3b, Balanus spongicola, scutum and tergum, external views. 

 3c, 3d, „ ,, „ „ internal views. 



3e, „ „ shell, enlarged from a recent specimen, the single fossil 



being young, and having been injured by examination. 

 Fig. 4a, Balanus concavus, shell (Coralline Crag specimen). 



Ab, „ „ internal view of part of the carina (to the left hand), of the ca- 



rino-lateral compartment, and of part of the lateral compart- 

 ment, showing the raised borders (r) on the rostral sides of 

 the sutures in the sheath (Italian Tertiary specimen). 

 Ac, ,, „ shell, var., with longitudinal ridges or ribs not prominent 



(Coralline Crag). 

 Ad, „ ,, smooth var. (Piedmont specimen). 



Ae, ,, ,, scutum, external view (Coralline Crag). 



4/, ,, ,, „ internal view do. 



Ag, „ ,, tergum, external view do. 



Ah, ,, „ scutum, internal view (Maryland, U.S.). 



M, „ ,, tergum, internal view do. 



4k, „ „ ,, external view do. 



41, ,, ,, scutum, external view (Portugal fossil, and recent). 



Am, ,, „ tergum, external view do. do 



An, „ „ scutum, internal view do. do. 



Ao, ,, „ tergum, external view, very large specimen (Turin). 



Ap, ,, „ scutum, small portion, at the rostral corner, highly magnified, 



very large specimen (Turin). 

 Fig. oa, Balanus porcatus, shell, nat. size (Red Crag). 



