2 BULLETIN 60, UNITED STATES NATIONAL MUSEUM. 



from North American waters, and no Verrucidae. The Pedunculata 

 now known from our coasts number 56 species and 9 subspecies, and 

 the Verrucidiv 5 species and 1 subspecies. 



A few notes on the distribution of the species ma}^ be useful. With 

 one exception, all of our pelagic cirripedes are very widely distributed 

 forms, already known, from many Atlantic and Pacific localities. One 

 pelagic species, Alepas pacifica^ materiall}" enlarges our knowledge of 

 a small and little-known group of forms commensal on large medusse. 

 Those having opportunity should especially look for barnacles of this 

 type. 



The deep-water forms, both of Lepadidai and Verrucidw, support 

 the opinions adv^anced by Hoek, Annandale, and others that deep-sea 

 cirripedes have a very wide distribution. The deep-water fauna of 

 the Atlantic is fairly homogeneous, many of the species from off our 

 coast being very closel}' related to those from the Azores and east- 

 ward, while some species of Scalpellmii range from off Nova Scotia to 

 southern Europe and south to Tristan da Cunha. The number of 

 very large species of Seal pellwm^ Pmcilasma, and Verruca^ found oft' 

 our east coast, is unequaled, so far as I know, in any area of equal 

 extent. A considerable number of North Atlantic species stand very 

 close to Pacific and Indian Ocean forms, and a few are probably iden- 

 tical specifically. 



Exclusive of pelagic forms, the species of the Atlantic and Pacific 

 coasts of the United States are distinct, with possibly one exception," 

 but several of the Calif ornian species are closely related to those of the 

 Atlantic. 



From the very scanty data at hand it seems that the Antillean region 

 is an area of specific differentiation, a number of very distinct specific 

 types, not related to known Atlantic forms, occurring there. A com- 

 parison of this fauna with the Panamic will doubtless prove interest- 

 ing, but nothing is yet known of Panamic cirripedes. 



In the generic nomenclature I have been oliliged to make various 

 changes from the ordinary usage, yet only in cases where the univer- 

 sally accepted rules of priority have been transgressed. A few new 

 generic and subgeneric terms are introduced, chieflj^ for groups nearl}^ 

 or quite unknown in the time of Darwin. 



The privilege of studying these barnacles I owe to Dr. Richard 

 Rathbun, assistant secretarj^ in charge of the United States National 

 Museum. I am indebted also to Prof. G. O. Sars for the gift of 

 examples of ScalpeUum. Finally I must thank Miss Helen Winches- 

 ter for her careful work in drawing the illustrations for this paper. 



aScalpellum regium latidorsum, an Atlantic form, specimens of which are labeled 

 as from a station off British Columbia. No Pacific species was taken with them. 



