THE SESSILE BARNACLES. 



89 



BALANUS AMPHITRITE Darwin. 



1789. t Balamis radiatus BRUGUIERE, Encyclopedic m&hodique, p. 108. 



1790. ? Lcpas purpurea SPENOLER, Skrivter af Naturhistorie Selskabet, vol. 1, 

 p. 172. 



1795. Lcpas balanoides Linnaeus, POLI, Testacea utriusque Sicilioe, p. 23, pi. 5, 



figs. 2-7. Not of Linnaeus. 



1815. Lcpas rarfiataWooD, General Conchology, pi. 7, fig. 7. 

 1815. ? Lcpas minor WOOD, General Conchology, pi. 7, fig. G. 

 1854. Balanus amphitrite DARWIN, Monograph, p. 240, with varieties communis, 



venustus, pallidits, niveiis, modestus, stutsburi, and p. 241, var. obscurus, 



varicgalus, and cirratus. 



1897. Balanus amphitrite Darwin, WELTNER, Verzeichuis, p. 264. 

 1907. Balanus carenatus GRUVEL, Mem. Asiatic Soc. of Bengal, vol. 2, No. 1, p. G. 

 1913. Balanus amphitrite Darwin, HOEK, 5i6o^a-Expeditie, Monographic 316, 



p. 107, with var. malayensis, p. 172, pi. 14, figs. 8-17. 



Distribution. Tropical and warm temperate seas. 



Next to B. tintinnabulum, this is the most widely distributed 

 Balanus, and it is also variable with numerous races. I have 

 attempted a revision of the American forms only. The concave 

 carina and notched scutum which characterize B. carenatus are 

 inconstant features in amphitrite; in fact, that form of carina is 

 occasionally assumed by almost any Balanus. Whether carenatus is 

 valid as a variety of amphitrite can be ascertained only when a revision 

 of the oriental forms of the species is undertaken. 



The typical form of B. amphitrite is that which Darwin called var. 

 communis, and figured on plate 5, figures 2e, 2Ji } 21. This form is a 

 common barnacle in the Philippines. 



In some Philippine forms of amphitrite the adductor ridge of the 

 scutum is very much reduced, making a close approach to the condi- 

 tion found in B. alatus and B. minutus of Hoek. These forms will be 

 illustrated in a report on Philippine barnacles now in preparation. 



