1909.] NATURAL SCIENCES OF PHILADELPHIA. 367 



A NEW SPECIES OF SCALPELLUM FROM BRITISH COLUMBIA. 



BY HENRY A. PILSBRY. 



Soalpellum (Arcoscalpellum) columbianum n. sp. Figs. 1, 2. 



The capitulum is much compressed, more than twice as long as wide, 

 white under a very thin smooth pale yellowish cuticle ; occludent border 

 straight, carinal border evenly arched; greatest width about median. 

 There is no sculpture aside from indistinct growth-lines. 



The scutum has parallel occludent and internal margins, and is rather 

 narrow, with apical uril'o. 



The tergum is long, triangular, its occludent margin short, arched, 

 apex slightly recurved; the scutal and carinal margins are very long 

 and nearly straight. 



The carina is very long, with well-developed parietes of nearly equal 

 width; dorsal face very narrow throughout, and deeply guttered, the 

 high bordering ribs about as wide as the intervening groove or gutter. 

 It is more curved near the apex, which is situated high, about at the 

 upper sixth of the carinal side of the tergum. At its base the carina 

 intrudes between the umbones of the carinal latera. 



The upper latus is roughly trapezoidal, the scutal and carinal 

 borders parallel, upper border oblique, basal border convex. 



The rostrum is minute, oblong, slightly contracted in the middle. 



The rostral latus is rather low, triangular, the upper and lower 

 margins converging toward the rostral apex. 



The inframedian latus is narrowly subtriangular, spreading above, 

 narrowed towards the base. The umbo is near or at the lower third. 



The carinal latus is subtriangular, the umbo projecting at the base 

 of the carina, far below the bases of the other plates. The carinal 

 border is straight above, becoming concave near the base. 



The peduncle is short, covered with scales, of which there are about 

 16 rows of about 10 scales each. They are not regularly arranged. 



Length of capitulum 8.5, width 3.4, diameter 1.3 mm.; length of 

 carina 7.25 mm.; length of peduncle 3 mm. (fig. 1). 



Length of capitulum 7.7, width 3.3 mm.; length of carina 6.8 mm., 

 of peduncle 4 mm. (fig. 2). 



Lowe Inlet, British Columbia. Type (fig. 1) No. 38,697 U. S. Nat, 



