70 



BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



According to Darwin, the segments of the sixth pair of cirri bear 

 six pairs of spines. 



The conic form is often not large: diameter 33 mm., height 38 mm. 

 (Pacasmayo). The cylindric forms are larger; diameter 40 mm., 

 height 50 mm. (Payta). The largest individual seen in which the 

 base is flattened measures about 67 mm. in greatest diameter, 85 mm. 

 height. It is from the coast of Peru. Some individuals have a very 

 long base, as in B. psittacus. One taken from a wreck at Payta is 

 150 mm. long, of which the parietes occupy hardly 40 mm.; greatest 

 diameter 42 mm. In these examples the vertical sides of the base are 

 longitudinally plicate, and clouded with white and livid purple. The 

 pocket-like cavity runs down to a point. 



B. t. concinnus is well defined by the speckled coloration of the 

 parietes, the sculpture of tergum and scutum, and the acute, over- 

 hanging adductor ridge of the latter. According to Darwin, the joints 

 of the last cirrus bear six pairs of spines instead of four. Like B. t. 

 californicus it is a strongly individualized form. Possibly both may 

 deserve specific rank. 



Darwin gives the locality west coast of South America. Gruvel 

 records it from the Straits of Magellan, on B. psittacus, also Aden and 

 French-Congo. The last two records, if really pertaining to concinnus, 

 must have been based on specimens taken to those places on ships. 

 The records of B. tintinnabulum communis from the west coast of 

 South America may possibly be based on specimens of concinnus. 



BALANUS TINTINNABULUM GALAPAGANUS, new subspecies. 



Plate 12, figs. 1, la, 16. 



Type. Cat. No. 48003, U.S.N.M., from Hood Island, Galapagos, 

 on a rock, Albatross, April 7, 1888. 



The barnacle is conic with a rather small orifice and smooth or 

 weakly ribbed parietes ; white or pink, with red lines on the parietes ; 

 radii whitish, usually grooved transversely, their summits level; 

 summits of the alse very oblique. 



Height 10 mm. ; diameter 15 mm. 



Height 10 mm.; diameter 13 mm. 



Scutum pale grayish-pink, flat, the tergal border not noticeably 

 deflected. Sculpture of close, sigmoid growth-ridges, no longitudinal 

 stride. Adductor ridge very small, merely an acute ledge alongside 

 the depressor muscle-impression. 



