THE SESSILE BARNACLES. 307 



ORIENTAL SPECIES. 

 CHTHAMALUS CHALLENGER! Hoek. 



Plate 72, figs. l-4a. 



1SS3. Chthamdliis chuUcngcri IIoek, ClmUcngcr Reports, Zoologj', vol. 8, 



p. 165, pi. 13, figs. 35-38. 

 1911. CIi Ilia null lis challcngcri Hoek, Kruger, Beitriige ziir Cirripe<lioiiCauna 



Ostasiens, p. 46, pi. 3, fig. 30. 



Distrihittion. — Japan ; Matsushima. 



The barnacle has rounded ribs, rather strong, ^vhite throughout, 

 not corroded, and smooth inside. The radii are very narrow. Carino- 

 rostral diameter 7.6 mm. 



The scutum is lengthened. Articular ridge prominent, its edge 

 bisinuate, being excavated above, tapering below the median promi- 



FlG. 87. CHTHAMALUS CHALLENGEIlIj MaTSUSHIMA. a, MANDIBLE. l), MAXILLA. C, TERMI- 

 NAL SEGMENT OF THE SHORTER UAMUS OF CIRRUS IT. d, SEVENTH SEGMENT OF CIRRUS VI. 

 e, INTERMEDIATE SEGMENT OF CIRRUS VI OF THE VARIETY FROM AYUKAWA, JAPAN. 



nence. xVdductor muscle pit small and rather deep, with a raised 

 rim forming a strong adductor ridge. Lateral depressor muscle pit 

 is very indistinct. 



The tergum is wide above, narrow below. Upper free portion con- 

 spicuously laminate. Articular ridge strong, the articular furrow 

 wide. There is no real spur, as the basiscutal angle is termina]. 

 The basal margin is deeply sinuated below the depressor muscle crests, 

 the strongly developed crests being borne on a triangular lobe of the 

 valve, as in many other species. 



The mandible is of the steUatus form, but the three points at the 

 lower extremity are much more sti'ongly developed and the finely 

 pectinated space above them is shorter (fig. S7a). 



