58 



BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



mits of the alas oblique. Opercular valves as in B. t. tintinnabulum, 

 the adductor ridge of the scutum often very low, a mere convexity of 

 the median part of the valve, but more emphatic in young individuals. 



Typical examples from ship bottoms are symmetrically conic and 

 very conspicuously striped. Diameter 50 mm. ; height 30 mm., more 

 or less (pi. 10, figs. 2a, 21, from a ship arriving in Philadelphia from 

 Hongkong and Java). 



A series collected at Zamboanga, Mindanao, by Dr. E. A. Mearns, 

 show the features assumed in then 1 natural habitat, on a rough sup- 

 port. These clustered specimens are more cylindrical than those 

 from ships, with larger aperture and less regular ribs, and in some 

 the base is deep, as usual with crowded barnacles. The color stripes 

 are usually less regular and often the color spreads over the whole 

 parietes toward their bases. The sheath has the remarkable rich 

 madder-brown color characteristic of the subspecies (pi. 10, figs. 3). 



W.eltncr (Verzeichnis, p. 260) reports this variety from Walfisch 

 Bay, southwest Africa. Various lots in the United States National 

 Museum are without locality or are from ships, like No. 41169, from 

 Dublin Bay (W. H. Dall), and other specimens on a ship from 

 Hongkong and Java. 



This form is very closely related to the typical form of tintinnab- 

 ulum. 



BALANUS TINTINNABULUM SPINOSUS (Gmelin). 



1791. Lepas spinosa GMELIN, Systema Naturae, ed. 13, p. 3213. 

 1798. Lepas echinata BOLTEN, Museum Boltenianum, p. 197. 

 1854. Balanus tintinnabulum, var. spinosus Gmelin, DARWIN, Monograph, p. 196, 

 pi. 1, fig. i. 



Convexly conical; rather thin, the parietes somewhat ribbed, the 

 ribs terminating in very long, slender, up-curved tubular spines. White 

 or violet-tinted toward the summit, tho spines usually colored. Ac- 

 cording to Darwin the scuta "externally were smooth; the adductor 



ridge was rather more distinct from the 

 articular ridge than in any other variety, 

 and the terg'a more plainly beaked." The 

 opercular valves are wanting in the speci- 

 men figured, from an unknown locality. 

 In size, this form is one of the smallest, 

 diameter 15 to about 20 mm. (fig. 10). 



From its frequent occurrence on ships' 

 bottoms associated with B. t. tintinna- 

 bulum, it may be presumed to be from 

 China or India, but it is certainly west African also, possibly colonized 

 by vessels from India by the Cape route. Weltner gives the localities 

 Siam, East Indies, and St. Helena for specimens in the Berlin Museum, 

 and Hoek reports small specimens, up to 7 mm. diameter, taken 



FIG. 10. BALANUS TINTINNABULUM 

 SPINOSUS X 2. 



