THE BARNACLES IN THE IT. S. NATIONAL MUSEUM. 



59 



The carina is evenly and strongly curved, with apical umbo. The 

 roof is flat, bounded by narrow but rather high lateral ribs. The 

 sides are wide and strongly sculptured with oblique riblets, which are 

 a little irregular or crenulate. The basal margin is straight. 



The upper lateral plate is quadrangular, the scutal and carinal mar- 

 gins straight and parallel. The scutal margin is more than twice as 

 long as the carinal. The tergal and ])asal margins are straight, sub- 

 equal, and shorter than the scutal. The umbo is terminal. 



There seems to be a triangular rostrum, wholly covered b}^ the 

 rostral latera, but visible in the type-specimen by reason of the broken 

 apices of these latera. The specimen being unique, could not be further 

 investigated to make certain the actual conditions. 



The rostral latus is trapezoidal, more than half as high as long. 

 The ventral margins of 

 the two plates are 

 straight and in con- 

 tact. The basal mar- 

 gin is quite short, and 

 probably in part cov- 

 ered by the inframe- 

 dian plate. The scu- 

 tal margin is long and 

 straight. 



The infra median 

 latus is narrowly tri- 

 angular, a little con- 

 tracted near the obtuse 

 apex. The basal mar- 

 gin is about half as 

 long as the plate. The 

 rostral and carinal latera are 

 above the inframedian plate. 



The carinal latus is large and irregularly rhombic. The dorsal 

 margin is curved and projects slighth' from the dorsal outline below the 

 base of the carina. The two plates meet below the carina in a straight 

 suture. The umbo does not project and is situated at the base of the 

 carina below the middle of the dorsal outline of the plate. Several 

 beaded ribs radiate from the umbones to the lower and dorsal margins 

 of the plates. 



The very short peduncle is covered with narrow, transversely elon- 

 gated scales, and clothed with a hair}^ cuticle. 



Length of the capitulum 14, breadth 7.5 mm. Length of the 

 peduncle 2.7 mm. Length of the carina 10.7, diameter at base 2.5 mm. 



This handsomely sculptured species is represented by a single exam- 

 ple from the type locality. It belongs to a group comprising S. 



a 



Fig. 22. — SCAI,PEI-LUM formosum 

 OF ROSTRUM; f, 



< 3. fl, LATERAL VIEW 

 CARINAL VIEW. 



in contact for a verv short distance 



