74 



BULLETIN 60, UNITED STATES NATIONAL MUSEUM. 



Near the apex on the lateral side there is a small rounded lobe; else- 

 where the lateral margin is nearly straight. The basal margin is 

 straight and oblique. 



The calcified portion of the tergum is V-shaped, the occludent branch 

 six-tenths the length of the carinal, which is much longer than the 

 scutum, and acute distall\\ The apex is erect and acute. 



The carina is evenh^ arcuate, with subterminal umbo. The roof is 

 flat, bounded by angles. The sides are narrow, a trifle wider near the 

 apex. 



The calcified portion of the upper lateral plate is V-shaped, the 



tergal branch about two-thirds as long as the scutal. Both branches 



are rounded distally. The scutal margin is noticeably concave near 



the apex. The umbo is acute, curved toward the 



scutum, and a small rounded calcified lobe extends 



beyond it. 



There is no rostrum. 



The rostral latus is wedge-shaped, narrower ven- 

 trally, about twice as long as high. 



The inframedian latus is minute, narrowly tri- 

 angular, with apical umbo. 



The carinal latus is triangular, the basal mar- 

 gin straight, shorter than the others. The lateral 

 margin is concave, the carinal margin nearly 

 straight. The umbo projects a trifle Imckward and 

 laterally, at the baso-carinal angle of the plate, and 

 against the base of the carina. 



The peduncle is short, with eight rows of about 

 eight narrow and transversely elongated, non-im- 

 bricating scales. 



Length of the capitulum 15, breadth 7.3 mm.; 

 length of peduncle 6 mm.; length of the carina 

 13.5, diameter at base 1.7 mm. 



Of this species a single specimen was taken. It is related to S. japrm- 

 icum Hoek, but difters conspicuously b}' the shapes of the upper and 

 the inframedian lateral plates, and the much narrower carina, as seen 

 in dorsal view, the basal width of the roof being only about one-eighth 

 of its length. Moreover, the summits of the terga are recurved in 

 S. japonicum^ erect and nearly straight in S. nipponense. S. inter- 

 medhnn Hoek, from the South Pacific, described fi'om a specimen 

 with the capitulum 9 mm. long, stands close to S. nipponetise, its more 

 fully calcifled plates being a character which would certainly be found 

 in the young of the Japanese species; yet from the different rela- 

 tive sizes of the lower plates, I think the two forms are specifically 

 distinct. (Fig. 29.) 



Fig. 29.— Scalpellum nip 

 poxense. l.\ter.\i. view 



X 3. 



