90 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



BALANUS AMPHITRITE ALBICOSTATUS, new subspecies. 

 Plate 20, figs. 1 to 4. 



1911. Balanus amphitrite, var. communis Darwin, KRUGER, Beitrage zur Cirri- 

 pedienfauna Ostasiens, Abh. math.-phys. Klasse K. Bayer. Akad. Wiss., 

 vol. 2, Suppl.-Bd., 6 Abhandlg., p. 51, fig. 102-104; pi. 1, fig. 7; pi. 4, fig. 40 

 (Hongkong, Dr. Schauinsland ; Yokohama, Dr. Haberer). ?Also var. niveus 

 Darwin, KRUGER, Abh. math.-phys. Klasse K. Bayer. Akad. Wiss., pi. 4, 

 fig. 35 (Making, Pescadores, Dr. Haberer). 



Type. Cut. No. 32950, U.S.N.M., from Japan. 



Distribution. Yedo Bay to Hongkong. 



The barnacle tapers slightly to the ample rhombic orifice. Color 

 varying from dark Indian red to dark livid purple with white ribs, 

 which may be moderately prominent or barely raised. Sheath short, 

 purplish. Radii very broad, purplish or pink tinted, their summits 

 not very oblique. 



The scutum has only weak traces of growth-ridges and very fine, 

 faint radial striae. The articular ridge is half the length of the tergal 

 margin. The adductor ridge stands rather farther from the articular 

 ridge than in ordinary amphitrite. A sharp little fold, sometimes 

 doubled, divides the articular furrow. 



The tergum is narrow and long. There is only a slight depression 

 running to the spur, which is narrow and typically long, separated 

 by its own width from the acute basiscutal angle, or nearer in some 

 lots. The carinal margin is short and arched, the basal margin 

 typically somewhat excavated on the carinal side of the spur. Crests 

 for the depressor muscles are strongly developed. 



The basis has sharp radial ridges within. Parietal tubes have 

 numerous transverse septa in the upper part, but in the lower half 

 they are rather large and open. The longitudinal septa between the 

 tubes "bifurcate at their bases close to the outer lamina, making an 

 irregular row of minute pores," the degree of development of this 

 structure being variable. 



Carinorostral diameter 16.5 mm.; height 10 mm. 



Carinorostral diameter 14 mm.; height 10 mm. 



Carinorostral diameter 12.5 mm.; height 8.5 mm. 



The labrum has one very small tooth on one side, two on the other. 

 The margins of the notch are shortly hairy (fig. ISa). 



The mandible (fig. 18&) has three strong teeth and two obtuse short 

 ones, the lower point being irregularly spinose. 



The maxilla has nine spines below the upper pair, the lower pair 

 larger, and standing on a slight projection. 



. The cirri could be examined very imperfectly, as they were much 

 broken in the dry specimens. The posterior cirri have five pairs of 

 spines on the segments. Third cirri not found. 



