642 DESCRIPTION OF PLATES, 2 5. 



Fig. 7 a, Balanus vinaceus, scutum, internal view ; 7 b, do. external 

 view ; 7 c, tergum, external view ; 7 d, basal edge of the 

 parietes of one of the compartments, showing the can- 

 cellated structure of the inner lamina. 



PLATE 3. 



Genus — Balanus. 



Fig. 1 a, Balanus Ajax ; 1 b, scutum external ; 1 c, tergum external ; 

 and 1 d, scutum, internal view. 



2 a, 2 b, Balanus stultus, scutum and tergum, external views ; 



2 c and 2 d, scutum and tergum, internal views. 



3 a, Balanus calceolus, 3b, variety; 3c, scutum, internal view; 



3 d, tergum, internal view; 3 e, spur of tergum toothed. 



4 a, Balanus galeatus ; 4b, Ac, scutum and tergum, internal view. 



5 a, 5 b, Balanus cymbiformis, scutum and tergum, internal view. 



6 a, Balanus navicula ; 6b, 6c, scutum and tergum, internal view; 



6 d, scutum, external view. 



7 a, Balanus trigonus ; 7 b and 7 c, scutum, external views, two 



varieties ; 7 d, scutum, internal view ; 7 e and 7f, tergum, 

 external views, two varieties. 



PLATE 4. 



Genus — Balanus. 



Fig. 1« and 1 b, Balanus spongicola, external views of scutum and tergum, 

 1 c, var. of the tergum, from a specimen from the 

 Cape of Good Hope ; 1 d, var. of the tergum from the 

 West Indies. 

 2 Balanus laevis. 



2 a, ,, „ fossil, elongated var., showing lower part 



of basal cup filled up with a cancellated 

 mass. 

 2 5 and 2 c, ,, „ scutum, external and internal view of. 

 2 d and 2 e, ,, ,, scutum (variety), internal and external 



view of. 

 2/, ,, n scutum (variety), external view. 



2 g, ,, ,, tergum, external view. 



3 a, Balanus perforatus, scutum, internal view ; 3 b, tergum, in- 



ternal view ; 3 c, tergunii var. external view. 



4 a, Balanus concavus (var. from Panama), scutum, internal 



view ; 4 b, scutum, external view ; 4 c, tergum, external 

 view: 4 c?, tergum, fossil, Coralline Crag; 4 e, rtergum, 

 fossil, Italy. 



PLATE 5. 



Genus — Balanus. 



Fig. 1 a, Balanus perforatus, — var. angustus. 

 \ b, ,, ,, „ Cranchii. 



1 c, ,, ,, ,, mirabilis. 



