342 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



PLATE 17. 



FIGS. 1-4. Balanus psittacus (Molina). Talcahuano Bay, Chile. Page 75. 

 5-8. Balanus tintinnabulum concinnus Darwin. Peru. Page 69. 



PLATE 18. 

 Balanus psittacus (Molina). Page 75. 



FIG. 1. Adults from Talcahuano Bay, Chile. Cat. No. 43482. Length of 

 right-hand specimen about 18 cm. Small barnacles growing on 

 the larger ones are Balanus Iccvis nltidus Darwin and Verruca 

 Icevigata Sowerby. 



2. Young individual from Valparaiso. Cat. No. 48007. Showing 



transient ribbed stage. Natural size. 



3. Young individuals from Arica. Cat. No. 48006, U.S.N.M. Ribbed 



form, in lateral and obliquely rostral views. Natural size. 



PLATE 19. 

 Balanus amphitrite nivcus Darwin. Page 92. 



FIGS. 1, la, 15, Ic. Vineyard Sound, Massachusetts. Terga and scuta of an indi- 

 vidual of group Ic. 

 Ic. Vineyard Sound, Massachusetts. Cat. No. 38313, U.S.N.M. 



Group growing on a pebble. 

 Id. Vineyard Sound, Massachusetts. Tergum of another specimen 



of group Ic, having the spur rounded distally. 

 2. Marco, Florida. Cat. No. 48008, U.S.N.M. Group growing on 



the back of a Crepidula. 



la, 26, 2c. Marco, Florida. Terga of three individuals of same group. 

 2d, 2e. Marco, Florida. Scuta of individuals of same group. 

 Figs. Ic and 2 natural size. 



PLATE 20. 



FIG. 1. Balanus amphitrite albicostatus Pilsbry. Yedo Bay, Japan. Cat. 

 No. 48011, U.S.N.M. Lateral view. Page 90. 



2-2b. B. a. albicostatus. Type. Cat. No. 32950, U.S.N.M. Lateral view, 

 tergum and scutum. 



3. B. a. albicostatus. Group on a quartz pebble, from the North 



Pacific Exploring Expedition. Cat. No. 48008, U.S.N.M. 



4. B. a. albicostatus. Hirado, Hizen. No. 1518, A.N.S.P. Rugged 



form. 



5-5e. Balanus amphitrite inexpectatus Pilsbry. Gulf of California. 



Cat. No. 12398, U.S.N.M. Type-specimen, growing on an oyster, 



with terga and scuta. Page 97. 



5c. Tergum of a smaller individual, showing variation in shape of the 



spur. 



