THE BARNACLES IN THE U. S. NATIONAL MUSEUM. 113 



able scutum has two very distinct arcuate ribs. The interlocking- ribs 

 of the carina and rostrum, below the strong- upper ones, are more dis- 

 tinct. The ledg-e-like area between the upper ai-ticular ridge of the 

 rostrum and the movable scutum is much wider, with strong rilj- 

 sculpture, and two narrow curved ribs. Greatest carino-rostral 

 length, 8.5 mm. ; breadth, 6.7 mm. ; height, 6.7 mm. These specimens 

 seem to show that there may be considerable individual variation in 

 Vei'ruca, if, indeed, the differences between them are individual and 

 not racial. In all other cases where I have been able to compare a 

 number of examples they have proved to be very constant. 



VERRUCA HOEKI, new species. 



Plate XI, figs. 4, 5, 6. 



Type.— Cat. No. 1493, U.S.N.M. 



Type-locality. — Alhatross Station 2750, north latitude 18-' 30', 'west 

 longitude 63^ 31', Anegada Passage, in 1:96 fathoms, bottom temp. 

 41.5- F. 



The shell is small, gray- white; laterally much compressed, the base 

 narrowly oval; ver}^ liigh, conspicuously leaning; the movable plates 

 lying parallel with the wall below them; sculpture very weak. 



The movable scutum is small, triangular, the apex but little curved. 

 The occludent and tergal margins curve down, the plate being thus a 

 little convex at the sides, flat in the middle. Except for a few faint, 

 wideh' spaced transverse grooves there is no sculpture. 



The tergum is nearl}^ square, the upper margin a trifle shorter than 

 the others. It is divided into two triangles b}^ a diagonal rib from 

 apex to baso-scutal angle. The scutal triangle has faint sculpture of 

 spaced grooves parallel to the scutal margin; the other area has similar 

 faint vertical grooves. The suture between scutum and tergum is 

 straight and simple. 



The fixed scutum is quadrangular, margins straight; the side mar- 

 gins vertical, at right angles to the base; the upper margin slopes 

 steepl3\ The apex is acute and projects a trifle. The surface is 

 w^eakly marked with growth lines and faint vertical strise. 



The fixed tergum is high and narrow, five-sided. The basal margin 

 is short, the side margins long, divergir j upward. The upper mar- 

 gins converge to the pointed apex. 



The rostrum rises to an acute, slightly recurved apex; it is curved, 

 forming the rounded end of the wall. Three weak ribs radiate from 

 the apex to the carinal margin. 



The carina is lower than the rostrum, square, the apex acute, 

 slightly projecting. A low rib along the upper margin terminates in 

 a lobe indenting the suture with the rostrum, which is elsewhere an 

 even line. 



4715— Bull. 60—07 8 



