236 DISCOVERY REPORTS 



Conchoderma virgatum f. hunteri (Owen, 1830). 



Conchoderma hunteri Darwin, 1851, Monogr. Lepadidae, p. 153. 



Conchoderma virgatum f. hunteri Broch., 1931, Vidensk. Meddel. Dansk. naturh. Foren. Kjeb. 91, 

 p. 28. 

 22. iv. 35. No locality given. Several specimens from ventral thoracic region of Exocaetus sp., 

 which flew on board. 



Distribution. Indian and Pacific Ocean. 



Discussion. The specimens of this collection were taken from a flying fish. This 

 variety was formerly noted from snakes and decapods. The typical form of Conchoderma 

 virgatum is taken also from Mola mola and Gymtiothoraxfavagineus {Lycodontis favaginea 

 (Schneider)). 



Genus Balanus da Costa, 1778 

 Balanus algicola Pilsbry, 191 6. 



Balanus algicola Pilsbry, 1916, Bull. U.S. Nat. Mus. No. 93, p. 72. 

 7. viii. 36. Simonstown, dry dock. Some specimens grouped round the spines of the second 

 dorsal fin of Squalus acutiformis. 



Distribution. South Africa. 



Discussion. This species, discovered by Pilsbry, 1916, is easily recognizable by its 

 opercular valves. It was first described on small individuals, fixed on algae. The 

 interesting find of this expedition shows that it does not only occur on algae. It is here 

 found on a spine of Squalus (Fig. 5), a rare habitat for the genus Balanus. According 



Fig. 5. Balanus algicola Pilsbry, 1916. Specimens fixed on spine of the 

 second dorsal fin of Squalus acutiformis. 



to Gruvel (1910), a small specimen of B. juaxillaris is found on a spine of Acanthias 

 vulgaris, also from Simonstown. Probably this specimen is to be preferred to Balatius 

 algicola, a species not known before 191 6. B. improvisus is also mentioned by Ciurea, 

 Monod and Dinulesco, 1933, from a fish, the mandible of Lucioperca lucioperca. From 

 other material I have found Balanus algicola fixed even on mussel shells. These examples 

 also show that the species is not always of very small size, as Pilsbry deduces from the 

 type material. The specimens were, like some of Pilsbry's specimens, violet-coloured. 



