THE SESRILE BATtNACLES. 25 



fifths tlio length of cirrus vi. A specimen from England examined 

 agrees with these proportions. 



This species, the type of the genus, is one of the more highly- 

 evolved forms, both in internal structure and the form and articula- 

 tions of the wall-plates. The fine, crowded growth lines are also a 

 peculiar feature. With V. Isevigata and V. spengleri, it should prob- 

 ably bo considered to form a section of the genus apart from the 

 deep-sea species. 



VERRUCA L^VIGATA (Sowerby.) 

 Plate 8, fig. 2. 



1827. Clitia Ixvigafa Sowerby, Genera of Recent and Fossil Shells. Plate of 



Clitia, figa. 1, 3. 

 1854. Verruca Ixvigata Sowerby, Darwin, Monograph, etc., p. 520, pi. 21, figa. 



3a, 36. 

 1897. Verruca Ixvigata Sowerby, Weltner, Verzeichnis, Archiv fur Natur- 



geschichte, Jahrg. 1897, vol. 1, p. 274. 

 1903. Verruca Ixvigata Sowerby, Gruvel, Nouv. Arch, du Museum (4), vol. 5, 



p. 99, pi. 1, fig. 10. 



Type. — Present location unknown; from "coast of South America, 

 adhering to Mytilus magcllanicus." 



Distrihution. — Tierra del Fuego to Peni (Darwin). 



Numerous individuals. Cat, Nos. 43480, 43481, are on a pair of 

 very large specimens of Balanus psiUacus (Mohna), from Talcahuano 

 Bay, Chile, Cat. No. 43482, R. E. C. Steams coU. One of these is 

 illustrated. V. Isevigata and V. stromia are the only Httoral species 

 of the genus known, and the former is the only species known from 

 South America, or, indeed, from any part of the eastern rim of the 

 Pacific. Smce its only near relatives live m the north Atlantic, its 

 ancestors probably spread westward in pre-Miocene times before the 

 elevation of the Isthmus of Panama. The individual figm'ed meas- 

 ures 6 mm. in carinorostral diameter. 



Group of V. alba. 



Boxlike, strongly sculptured forms, externally like the Group of 

 V. cahtlieca, but differmg in the cirri, which are very slender; cirri 

 i and ii havmg very unequal rami, the anterior branch about one- 

 third as long as the posterior; cirrus iii with somewhat unequal rami, 

 iv to vi similar with subequal rami; tcu'minal appendages very long. 



VERRUCA ALBA Pilsbry. 



Plate 2, figs. 1-16, 2. 

 1907. Verruca nexa alba Pilsbry, U. S. Nat. Mua., Bull. CO, p. 107, pi. 11, figs. 7, 8. 



Type.— CsJu. No. 9474, U. S. N. M. 



Type-locality. — Albatross station 2317, Straits of Florida, north 

 latitude 24° 25' 45"; west longitude 81° 46' 45", in 45 fathoms, 

 bottom temperature 75° F., seated on a sea-urchin spine. Other 



