54 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



B. campbelli Filhol. 1 Campbell Island. 



B. vinaceus Darwin. "West Coast of South America." 



BALANUS TINTINNABULUM (Linneeus). 



1758. Lepas tintinnabulum LINNAEUS, Systema Natures, ed. 10, p. 668. 



1854. Balanus tintinnabulum Linnaeus, DARWIN, Monograph, etc., p. 194, with 



varieties cornmunis, vesiculosus, validus, zebra, crispatus, p. 195, and varieties 



spinosus, coccopoma, concinnus, inlermedius, occator, d'orbignyi, p. 196. 

 1883. Balanus tintinnabulum Linnaeus, HOEK, Zool. CJiallenger Exped., vol. 25, 



Report on the Cirripedia, p. 147. 

 1897. Balanus tintinnabulum Linuseus, WELTNER, Verzeichnis der bisher beschrie- 



benen receiiten Cirripedienarten, in Archiv fur Naturgeschiehte, p. 260. 

 1903. Balanus tintinnabulum. Linuseus, GRUVEL, Nouvelles Archives du Museum 



d'Histoire Naturelle, ser. 4, vol. 5, p. 125. 

 1913. Balanus tintinnabulum Linnaeus, HOEK, The Cirripedia of the Siboga 



Expeclitie, Monographie 316, p. 164, with variety validus, pp. 164, 166, pi. 



16, figs. 16-19; var. costalus, p. 165, pi. 14, figs. 5, 6; var. plicatus, p. 165, 



pi. 14, fig. 7. 



Distinguished from other species of the same subgenus by the 

 broad, triangular terga, with long spur remote from the basiscutal 

 angle, and without crests for the depressor muscle; the wide radii 

 with the summits usually subhorizontal; the fine, straight, regular 

 sutural septa, which are denticulate on botli sides (pi. 10, fig. 2). 

 This last character will distinguish large specimens without opercular 

 valves from such similar species as B. psittacus, but of course it can 

 be seen only by breaking the compartments apart. 



Balanus tintinnabulum may be said to be, in a way, the best known 

 of sessile barnacles, since for three or four hundred years it has con- 

 stantly been brought into almost every port of deep-sea traffic in 

 the world, is common in museums, and in the last century or two 

 it has frequently been figured and described. But the very circum- 

 stances that it is freely carried about, and that most of the specimens 

 accessible to zoologists have been from ships' bottoms, have effec- 

 tually befogged the zoogeographic study of the races, several of 

 which are known from ships' bottoms only. Published records of 

 distribution are not to be trusted implicitly, since in many cases they 

 were probably based upon specimens from ships, even when not so 

 stated. Moreover, there seems reason to believe that there are 

 many more local subspecies than were known to Darwin, and this 

 may have led to wrong identifications and therefore false locality 

 records of the Darwinian subspecies. 



We do not know to what extent the subspecies may hybridize when 

 gathered together by vessels successively entering waters inhabited 

 by different forms. So far as I know, no evidence of hybridism has 

 been found. 



1 The systematic position of B. campbelli is uncertain, as the characters of walls and basis are unknown. 

 M. Gruvel, who has figured the opercular valves, considers it related to B. decorus. 



