344 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



Plate 25. 



Figs. 1-lc. Balanus calidtts Pilsbry. Albatross station 2372, off western Flor- 

 ida. Opercular valves and lateral view of type-specimen. Cat. 

 No. 10069, U.S.N.M. Page 118. 



2. Balanus spongicola Brown. Dublin Bay, Cat. No. 12145, U.S.N.M. 



Lateral view of specimen seated on Pectcn opercularis. Natural 

 size. Page 115. 



3. B. spongicola. Exmouth, Devon. Cat. No. 12078, U.S.N.M. Lat- 



eral view of specimen seated on a sandstone pebble. Natural 

 size. 

 4-4c. B. spongicola. Patros Island, Brazil. Cat. No. 14144, U.S.N.M, 

 Lateral view of group, and opercular valves. 



Plate 26. 



Balanus trigoims Darwin. Page 111. 



Figs. 1-9. Type figures of Balamis armatus F. INIiiller, copied photographically 

 from IMiiller's plate, c, carina ; r, rostrum. 

 10, 10«. Internal and external views of the tergum, from the same source. 



11. External view of the scutum, from the same source. 

 12, 12a. Lateral view of wall and inside of tergum of a West Indian speci- 

 men, taken from the bottom of a Cape Cod whaler. Cat. No. 

 21550, U.S.N.M. Length, 8.3 mm. 

 13-13e. Group covering the shell of a Tegula, and opercular valves. San 

 Diego, California. Cat. No. 11153, U.S.N.M. 



Plate 27. 



Figs. 1, la. Balamis Iwvis Bruguiere. Gregory Bay, Strait of Magellan. Cat. 



No. 48012, U.S.N.M. Scuta. Page 120. 



2-2(1. B. I. nitidus Darwin. Arica, Chile. Page 122. 



3, 3a, SI). B. Iwvis. Albatross station 2773, east coast of Patagonia. Cat. 



No. 48013, U.S.N.M. Groups and spongy bases of specimens 



which grew on pebbles. Page 120. 



4. B. I. nitidus. Callao. Cat. No. 9209, U.S.N.JI. Specimens forming 



a ball, wholly concealing the original supporting object. Page 122. 

 5\ B. I. nitidus. Arica, Chile. Scutum with groove much reduced. 

 Figs. 3^ about natural size. 



Plate 28. 



Figs. 1, la. Balanus grcgarlus (Conrad). San Pablo formation, Salinas Val- 

 ley, Monterey County, California. Detached basis, upper and 

 basal views, the latter natural size. Page 126. 



2. B. gregarius. Lateral view of a biconic example 104 mm. in 



greatest diameter. 



3. B. gregarius. Section about midway of the basis of an elongated 



example, viewed from above. Natural size. 



4. Balanus Iwvis coquimbensis Sowerby. Opened longitudinally to 



show the septa of the basis. Somewhat enlarged. Page 122. 



The specimens illustrated in figs. 1-3 are property of the United States Geological 



Survey. 



